Radiation-curable ink composition and image recording method

ABSTRACT

To provide a radiation-curable ink composition that can form a high-quality image on not only liquid absorbing materials to be recorded but also non-liquid absorbing materials to be recorded, is superior in curing properties in air, and is superior in storage stability, color tone, light fastness and water resistance of ink, and also to provide an image recording method. The radiation-curable ink composition comprises a monomer having a polymerizable group selected from the group consisting of an acryloyl group, a methacryloyl group, an allyl group, and a vinyl group, an oil-soluble dye, and from 0.005 to 1% by weight of a storage stabilizer, wherein the oil-soluble dye is dissolved in the ink.

FIELD OF THE INVENTION

[0001] The present invention relates to an ink composition containing anoil-soluble dye, which is curable with radiations, and to an imagerecording method using the ink composition.

BACKGROUND OF THE INVENTION

[0002] Aqueous ink compositions involved various defects. That is, inthe case where the aqueous ink composition is printed on plain paper, itis inferior in water resistance and is liable to cause blotting (i.e.,blurring). Further, in the case where it is printed on a non-waterabsorbing material to be recorded, such as plastics, since attachment(i.e., adhesion) of ink droplets is poor, an image cannot be formed;since drying of the solvent as used is extremely slow, it is required todry printed materials immediately after printing without being piled up;and the resulting image is liable to cause blotting.

[0003] In order to solve these problems, EP997508A1 discloses inkjetinks that are cured with radiations and fixed. However, since thedisclosed inkjet inks use a pigment dispersion as a coloring agent, thetransparency is poor, and the color tone is not satisfactory, and hence,it is difficult to obtain photographic images. Further, there wasinvolved a problem such that nozzles are clogged by coagulation of thepigment so that it is difficult to stably eject the ink.

[0004] As means for solving this problem, it may be considered to employa method of using a dye as the coloring agent. However, the dye verylikely worsens the radical polymerization properties, and hence, it wasdifficult to use it for curable inks. U.S. Pat. No. 4,303,924 disclosesinks in which a dye not retarding the curing is used. However, this U.S.patent does not definitely describe a guideline of selection of aneffective dye. Moreover, according to the conditions illustrated in theU.S. patent, the dye density is low, and the curing conditions undernitrogen, which are free from polymerization retardation by oxygen, areused. In the case where the dye density is increased, or the curing iscarried out in air, the curing becomes extremely difficult. Accordingly,for the practical use, there is a large restriction in facilities forproviding the conditions under nitrogen.

[0005] In addition, the inks as disclosed in the U.S. patent containconductive salts, and in many cases, these conductive salts are poor insolubility in the ink. Accordingly, there was a possibility that theseconductive salts deposit during the storage over a long period of time,resulting in poor printing.

SUMMARY OF THE INVENTION

[0006] The present invention is to solve the foregoing various problemsof the related art and to achieve the following object. That is, anobject of the present invention is to provide an ink composition thatcan undergo printing with high quality on not only the conventionalpapers but also non-water absorbing materials to be recorded, such asplastics and metals, is superior in curing properties in air, and issuperior in storage stability, color tone, light fastness, and waterresistance of ink and to provide an image recording method.

[0007] Specifically, in order to achieve the foregoing object, thepresent invention provides the following means.

[0008] (1). A radiation-curable ink composition comprising a monomerhaving a polymerizable group selected from the group consisting of anacryloyl group, a methacryloyl group, an allyl group, and a vinyl group,an oil-soluble dye, and from 0.005 to 1% by weight of a storagestabilizer, wherein the oil-soluble dye is dissolved in the ink.

[0009] (2) The radiation-curable ink composition as set forth in (1) asabove, further comprising a photopolymerization initiator.

[0010] (3) The radiation-curable ink composition as set forth in (1) or(2) as above, which does not substantially contain water or conductivesalts.

[0011] (4) The radiation-curable ink composition as set forth in any oneof (1) to (3) as above, wherein a content of a dispersion medium otherthan the monomer, or a solvent is 20% by weight or less.

[0012] (5) The radiation-curable ink composition as set forth in any oneof (1) to (4) as above, wherein the oil-soluble dye has an oxidationpotential is higher than 1.0 V against SCE.

[0013] (6) The radiation-curable ink composition as set forth in any oneof (1) to (5) as above, wherein the oil-soluble dye is at least onemember selected from cyan dyes, magenta dyes, yellow dyes, and blackdyes.

[0014] (7) The radiation-curable ink composition as set forth in any oneof (1) to (6) as above, wherein the oil-soluble dye is at least onemember selected from dyes represented by the following general formula(I):.

[0015] wherein Q represents an atomic group necessary such that thecompound represented by the general formula (I) absorbs light in avisible region and/or a near infrared region; A represents —NR⁵R⁶ or ahydroxyl group; R⁵ and R⁶ each independently represents a hydrogen atom,an alkyl group, an aryl group, or a heterocyclic group; B¹ represents═C(R ³)— or ═N—; B² represents —C(R⁴)═ or —N═; R¹, R², R³, and R⁴ eachindependently represents a hydrogen atom or a substituent; and R¹ andR², R¹ and R⁵, R⁵ and R⁶, R³ and R⁵, or R³ and R⁴ may be taken togetherto form a ring;

[0016] dyes represented by the following general formula (A-I):

[0017] wherein X₁, X₂, X₃, and X₄ each independently represents a groupselected from —SO—Z, —SO₂—Z, —SO₂NR₁R₂, —CONR₁R₂, —CO₂R₁, and a sulfogroup; Z represents a substituted or unsubstituted alkyl group, asubstituted or unsubstituted cycloalkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group; R₁ and R₂ each independentlyrepresents a hydrogen atom, a substituted or unsubstituted alkyl group,a substituted or unsubstituted cycloalkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group, provided that R₁ and R₂ do notrepresent a hydrogen atom at the same time; M represents a hydrogenatom, a metal element, a metal oxide, a metal hydroxide, or a metalhalide; Y₁, Y₂, Y₃, and Y₄ each independently represents a hydrogen atomor a monovalent substituent; and a₁ to a₄ and b₁ to b₄ represent thenumbers of X₁ to X₄ and Y₁ to Y₄, respectively and each independentlyrepresents an integer of from 0 to 4, provided that the total sum of a₁to a₄ is 2 or more and 16 or less; and dyes represented by the followinggeneral formula (Y—I):

A—N═N—B  (Y—I)

[0018] wherein A and B each independently represents an optionallysubstituted heterocyclic group.

[0019] (8) An ink set of the radiation-curable ink composition as setforth in any one of (1) to (5) as above, comprising three inks of amagenta ink containing the dye represented by the general formula (I), acyan ink containing the dye represented by the general formula (A—I),and a yellow ink containing the dye represented by the general formula(Y—I).

[0020] (9) An image recording method comprising undergoing recordingusing the radiation-curable ink composition as set forth in any one of(1) to (7) as above and then irradiating with radiations to achievecuring.

[0021] (10) The image recording method as set forth in (9) as above,wherein the recording is achieved by any one inkjet mode of chargecontrol mode, pressure pulse mode, and acoustic inkjet mode and thenirradiating with radiations to achieve curing.

DESCRIPTION OF THE INVENTION

[0022] (Ink composition)

[0023] The ink composition according to the present invention is an inkcomposition that is cured with radiations (radiation-curable inkcomposition), comprising a: monomer having a polymerizable group, anoil-soluble dye, and a storage stabilizer, wherein the oil-soluble dyeis dissolved in the ink. The ink composition may further contain othercomponents to be properly chosen, if desired.

[0024] As the radiations for proceeding with the polymerization of themonomer are employable α-rays, γ-rays, X-rays, ultraviolet rays, visiblerays, and electron beams. Especially, the use of ultraviolet rays orvisible rays is preferable from the standpoints of cost and safety, withthe use of ultraviolet rays being particularly preferred.

[0025] In the case where ultraviolet rays or visible rays are used asthe radiations, a photopolymerization initiator for initiating thepolymerization is used in combination. The radiation-curable inkaccording to other configuration of the present invention contains aphotopolymerization initiator for initiating the polymerization of themonomer.

[0026] <Monomer>

[0027] The monomer that is used in the present invention (hereinafterreferred to as “monomer of the present invention”) is a compound havinga polymerizable double bond (hereinafter referred to as “polymerizablegroup”), which is solidified by imparting-energies such as ultravioletrays, heat, and electron-beams. In the monomer, the use of abifunctional or polyfunctional compound (hereinafter referred to as“polyfunctional monomer”) is essential, and a monofunctional compound(hereinafter referred to as “monofunctional monomer”) for the viscosityadjustment, the adjustment of crosslinking density, and the control ofphysical properties (such as strength and adhesion) after curing.

[0028] Examples of the polymerizable group include an acryloyl group, amethacryloyl group, an allyl group, a vinyl group, and an internallydouble bonding group (such as maleic acid). Of these, an acryloyl groupand a methacryloyl group are preferred because they can be cured withlow energies, with an acryloyl group being particularly preferred.

[0029] As the polyfunctional monomer are enumerated vinylgroup-containing aromatic compounds; acrylates that are an ester of adihydric or polyhydric alcohol and acrylic acid or methacrylic acid;acrylamides that are an amide of a dihydric or polyhydric amine andacrylic acid or methacrylic acid; polyester acrylates obtained byintroducing acrylic acid or methacrylic acid into an ester obtained bybonding a polybasic acid and a dihydric alcohol or into apolycaprolactone; polyether acrylates obtained by introducing acrylicacid or methacrylic acid into an ether obtained by bonding an alkyleneoxide and a polyhydric alcohol; epoxy acrylates obtained by introducingacrylic acid or methacrylic acid into an epoxy: resin, or by reacting adihydric or polyhydric alcohol with an epoxy-containing monomer;urethane acrylates having a urethane bond; amino resin acrylates;acrylic resin acrylates; alkyl resin acrylates; spiran resin acrylates;silicone resin acrylates; reaction products of an unsaturated polyesterand the foregoing photopolymerizable monomer; and reaction products of awax and the foregoing photopolymerizable monomer. Of these arepreferable acrylates, polyester acrylates, polyether acrylates, epoxyacrylates, urethane acrylates, acrylic resin acrylates, silicone resinacrylates, and reaction products of an unsaturated polyester and theforegoing photopolymerizable monomer, with acrylates, polyesteracrylates, polyether acrylates, epoxy acrylates, and urethane acrylatesbeing particularly preferred.

[0030] Examples of the polyfunctional monomer include divinylbenzene;1,3-butanediol diacrylate; .1,6-hexanediol diacrylate; pentaerythritoltriacrylate; trimethylolpropane triacrylate; dipentaerythritolhexaacrylate; 1,6-acryloyl-aminohexane; hydroxypivalic acid esterneopentyl glycol diacrylate; polyester acrylates having a (meth)acryloyl group at the molecular chain terminals of a polyester having amolecular weight of from 500 to 30,000, which comprises a dibasic acidand a dihydric alcohol; polyethylene glycol diacrylate; epoxy acrylateshaving a molecular weight of from 450 to 30,000, which contain abisphenol (A, S or F) skeleton (i.e., basic structure); epoxy acrylateshaving a molecular weight of from 600 to 30,000, which contain aphenolic novolak resin skeleton; reaction products of a polyhydricisocyanate having a molecular weight of from 350 to 30,000 and ahydroxyl group-containing (meth)acrylic acid monomer; andurethane-modified compounds having a urethane bond in the moleculethereof.

[0031] As the monofunctional monomer are enumerated substituted orunsubstituted (meth)acrylates; substituted or unsubstituted styrenes;substituted or unsubstituted acrylamides; vinyl group-containingmonomers (such as vinyl esters, vinyl ethers, and N-vinylamides); and(meth)acrylic acid. Of these are preferable substituted or unsubstituted(meth)acrylates, substituted or unsubstituted acrylamides, vinyl esters,and vinyl ethers, with substituted or unsubstituted (meth) acrylates andsubstituted or unsubstituted acrylamides being particularly preferred.

[0032] Examples of the monofunctional monomer include hydroxyethylacrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate,dicyclopentenyl acrylate, 2-acryloyloxyethyl phosphate, allyl acrylate,N,N-dimethylaminoethyl acrylate, N,N-dimethyl acrylamide,N,N-diethylaminopropyl acrylamide, N-butoxymethyl acrylamide, acryloylmorpholine, 2-hydroxyethyl vinyl ether, N-vinylformamide,N-vinylacetamide, 2-cyclohexylcarbamoyloxyethyl acrylate, acrylatescontaining a polybutyl acrylate site in the ester moiety, and acrylatescontaining a polydimethylcyclohexane site in the ester moiety.

[0033] A content of the monomer of the present invention is preferablyin the range of from 50 to 99.6% by weight, more preferably from 70 to99.0% by weight, and most preferably from 80 to 99.0% by weight in theink composition. Any of the foregoing monomers can be used in thepresent invention so far as the effects of the present invention areobtained, but it is more preferable to select the monomer from thosehaving high safety. The monomer having high safety as referred to hereinis one having a small value of PII (primary skin irritation index). Themonomer preferably has PII of 3.0 or less, more preferably 2.0 or less,further preferably 1.0 or less, and most preferably 0.5 or less.

[0034] <Photopolymerization initiator and sensitizer>

[0035] With respect to the photopolymerization initiator, there are noparticular limitations so far as a radical generated by light or otheractive species is reactive with the polymerizable double bond in themonomer.

[0036] As the photopolymerization initiator are generally knownacetophenone derivatives, benzophenone derivatives, benzil derivatives,benzoin derivatives, benzoin ether derivatives, benzyl dialkyl ketalderivatives, thioxanthone derivatives, acylphosphine oxide derivatives,metal complexes; p-dialkylaminobenzoic acids, azo compounds, andperoxide compounds. Of these are preferable acetophenone derivatives,benzil derivatives, benzoin ether derivatives, benzyl dialkyl ketalderivatives, thioxanthone derivatives, and acylphosphine oxidederivatives, with acetonephenone derivatives, benzoin ether derivatives,benzyl dialkyl ketal derivatives, and acylphosphine oxide derivativesbeing particularly preferred.

[0037] Examples of the photopolymerization initiator includeacetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone,p-dimethylaminopropiophenone, benzophenone, p,p′-dichlorobenzophenone,p,p′-bisdiethylaminobenzophenone, Michler's ketone, benzil, benzoin,benzoin methyl ether, benzoin isopropyl ether, benzoin n-propyl ether,benzoin isobutyl ether, benzyl dimethyl ketal, 1-hydroxy-cyclohexylphenyl ketone, tetramethylthiuram monosulfide, thioxanthone,2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,2-dimethylpropioyldiphenylphosphine oxide, 2-methyl-2-ethylhexanoyl diphenylphosphineoxide, 2,6-dimethylbenzoyl diphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide,bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide,2,3,6-trimethylbenzoyl diphenylphosphine oxide,bis(2,3,6-trimethylbenzoyl)-phenylphosphine oxide,2,4,6-trimethoxybenzoyl diphenylphosphine oxide, 2,4,6.-trichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyl naphthylphosphonate,bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-di-fluoro-3-(1H-pyrrol-1-yl)-finyl)titanium,p-dimethylaminobenzoic acid, p-diethylaminobenzoic acid,azobisisobutyronitrile, 1,1′-azobis(1-acetoxy-1-phenyethane), benzoinperoxide, and di-t-butyl peroxide.

[0038] In addition, the photopolymerization initiators as described onpages 65-148 of Kiyoshi Kato, Shigaisen Koka Shisutemu (UltravioletRay-Curing System), by Sogo Gijutsu Center K.K. (1988) can be enumeratedas the photopolymerization initiator. The photopolymerization initiatormay be used singly or in admixture of two or more thereof. Further, thephotopolymerization initiator may be used in combination with asensitizer.

[0039] Further, it is preferred that the photopolymerization initiatordoes not cause thermal decomposition at temperatures up to 80° C. Whenan initiator causing thermal decomposition at temperatures of 80° C. orlower is used, a problem in the product preservation arises, and hence,such is not desired.

[0040] With respect to the amount of the photopolymerization initiatorto be used, there are no particular limitations. However, it ispreferably from 0.5 to 20% by weight, more preferably from 1 to 15% byweight, and most preferably from 3to 10 % by weight. When the amount ofthe photopolymerization initiator to-be used is less than 0.5% byweight, the curing does not take place, or the curing time is long. Onthe other hand, when it exceeds 20% by weight, deposition or separationlikely occurs with the lapse of time of dissolution, or the performanceof the ink after curing, such as strength and resistance to rubbing, maypossibly be worsened, and hence, such is not desired.

[0041] The sensitizer is not activated upon irradiation with light whenused alone. However, when used in combination with thephotopolymerization initiator, the sensitizer gives rise to more effectsthan those when the photopolymerization initiator is used alone. Ingeneral, amines are useful as the sensitizer. The reasons why theaddition of an amine accelerates the curing rate reside in that (1) itsupplies hydrogen to the photopolymerization initiator by the hydrogenextraction action and that (2) though generated radicals are bound tooxygen molecules in air to worsen the reactivity, the amine is dissolvedinto the composition to capture oxygen.

[0042] As the sensitizer are enumerated amine compounds (such asaliphatic amines, aromatic group-containing amines, piperidine, reactionproducts of an epoxy resin and an amine, and triethanolaminetriacrylate), urea compounds (such as allylthiourea and p-toylthiourea),sulfur compounds (such as sodium diethyl dithiophosphate and solublesalts of aromatic sulfinic acids), nitrile-based compounds (such asN,N-diethyl-p-aminobenzonitrile), phosphorus compounds (such astri-n-butyl phosphine and sodium diethyl dithiophosphide), nitrogencompounds (such as Michler's ketone, N-nitrisohydroxylamine derivatives,oxazolidine compounds, tetrahydro-1,3-oxazine compounds, and condensatesof formaldehyde or acetaldehyde and a diamine), and chlorine compounds(such as carbon tetrachloride and hexachloroethane).

[0043] An amount of the sensitizer to be used is from 0 to 10% byweight, preferably from 0.1 to 10% by weight, and more preferably from0.2 to 5% by weight. The selection and combination of thephotopolymerization and the sensitizer and the compounding ratio thereofcan be properly chosen depending upon the type of the radiations andmonomer to be used and the device to be used.

[0044] <Oil-soluble dye>

[0045] As the magenta dye of the oil-soluble dyes that can be used inthe present invention, arbitrary magenta dyes can be used. As themagenta dye can be enumerated aryl or heteryl azo dyes having, forexample, a phenol, a naphthol, or an aniline as a coupling component;azo methine dyes having, for example, a pyrazolone or apyrazolotriazole. as a coupling component; methine dyes such asarylidene dyes, styryl dyes, merocyanine dyes, and oxonol dyes;carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, andxanthene dyes; quinone-bsed dyes such as naphthoquinone, anthraquinone,and anthrapyridone; and condensed polycyclic dyes such as dioxazinedyes.

[0046] Especially, compounds represented by the general formula (I)(hereinafter referred to as “compound (I)”) are preferred.

[0047] In the general formula (I), Q represents an atomic groupnecessary such that the compound represented by the general formula (I)absorbs light in a visible region and/or a near infrared region, andpreferably a residue of a diazo component. A represents —NR⁵R⁶ or ahydroxyl group, and preferably —NR⁵R⁶. R⁵ and R⁶ each independentlyrepresents a hydrogen atom, an alkyl group, an aryl group, or aheterocyclic group. B¹ represents ═C(R³)— or ═N—; B² represents —C(R⁴)═or —N═; R¹, R², R³, and R⁴ each independently represents a hydrogen atomor a substituent. R¹ and R², R¹ and R⁵, R⁵ and R⁶, R³ and R⁵, or R³ andR⁴ may be taken together to form a ring.

[0048] With respect to the substituent of R¹, R², R³, or R⁴, there areno particular limitations. But, the examples thereof include a halogenatom, an aliphatic group, an aromatic group, a heterocyclic group, acyano group, a carbamoyl group, an alkoxycarbonyl group, anaryloxycarbonyl group, a heterocyclic oxycarbonyl group, an acyl group,a hydroxyl group, an alkoxy group, an aryloxy group, a heterocyclic oxygroup, a silyloxy group, an acyloxy group, a carbamoyloxy group, analkoxycarbonyloxy group, an aryloxycarbonyloxy group, an amino groupsubstituted with an alkyl group, an aryl group or a heterocyclic group,an acylamino group, a ureido group, a sulfamoylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, an alkyl- orarylsulfonylamino group, a heterocyclic sulfonylamino group, a nitrogroup, an alkyl, aryl or heterocyclic thio group, an alkyl- orarylsulfonyl group, a heterocyclic sulfonyl group, an alkyl- orarylsulfinyl group, a heterocyclic sulfinyl group, and a sulfamoylgroup. Each of these substituents may further be substituted.

[0049] Of the compounds represented by the general formula (I) arepreferable those represented by the following general formula (I-1).

[0050] In the general formula (I-1), D represents, a 5-memberedheterocyclic group. As the hetero atom of the 5-membered heterocyclicgroup can be enumerated N, O, and S. D is prefereably anitrogen-containing 5-membered heterocyclic group. The heterocyclic ringmay be condensed with an aliphatic ring, an aromatic ring, or otherheterocyclic ring.

[0051] Preferred examples of the heterocyclic ring of D include apyrazole ring, an imidazole ring, a thiazole ring, an isothiazole ring,a thiadiazole ring, a benzothiazole ring, a benzoxazole ring, and abenzoisothiazole ring. Each of these heterocyclic rings may further havea substituent. Among them are preferable a pyrazole ring, an imidazolering, an isothiazole ring, a thiadiazole ring, and a benzothiazole ringrepresented by the following general formulae (a) to (f).

[0052] In the general formulae (a) to (f) , R⁷ to R²⁰ each represents ahydrogen atom or a substituent. As the substituent, the samesubstituents as enumerated above for R¹, R² or R⁴ can be enumerated.

[0053] Among the general formulae (a) to (f), the pyrazole ring and theisothiazole ring represented by the general formulae (a) and (b) arepreferred, and the pyrazole ring represented by the general formula (a)is most preferred.

[0054] Preferred examples of the substituent represented by R¹ or R²include a hydrogen atom, an alkyl group, an alkoxycarbonyl group, acarbamoyl group, and a cyano group. Each of these groups may furtherhave a substituent.

[0055] Preferred examples of the substituent represented by R⁴ include ahydrogen atom, a halogen atom, an aliphatic group, an aromatic group, ahydroxyl group, an alkoxy group, an aryloxy group, an acyloxy group, aheterocyclic oxy group, an amino group substituted with an alkyl group,an aryl group or a heterocyclic group, an acylamino group, a ureidogroup, a sulfamoylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, and an alkyl, aryl or heterocyclic thiogroup, with a hydrogen atom, a halogen atom, an alkyl group, a hydroxylgroup, an alkoxy group, an aryloxy group, an acyloxy group, an aminogroup substituted with an alkyl group, an aryl group or a heterocyclicgroup, and an acylamino group being more preferred. Especially, ahydrogen atom, an arylamino group, and an amide group are mostpreferred. Each of these groups may further have a substituent.

[0056] Preferably, R⁵ and R⁶ each represents a hydrogen atom, an arylgroup, or a heterocyclic group. Each of these groups may further have asubstituent. However, it is preferred that any one of R⁵ and R⁶ does notrepresent a hydrogen atom.

[0057] R¹ and R⁵, or R⁵ and R⁶ may be taken together to form a 5- or6-membered ring.

[0058] In the case where the substituent represented by each of D, R¹,R², R⁴, R⁵, and R⁶ further has a substituent, the substituents asenumerated above for R¹, R², and R⁴ can be enumerated as thesubstituent.

[0059] In the specification and claims of this application,, the term“aliphatic group” means an alkyl group, a substituted alkyl group, analkenyl group, a substituted alkenyl group, an alkynyl group, asubstituted alkynyl group, an aralkyl group, and a substituted aralkylgroup. The aliphatic group may be branched or cyclic. The aliphaticgroup preferably has from 1 to 20 carbon atoms, and more preferably from1 to 16 carbon atoms. As the aryl moiety of the aralkyl group or thesubstituted aralkyl group,, phenyl or naphthyl is preferred, and phenylis particularly preferred.

[0060] Examples of the aliphatic group include methyl, ethyl, butyl,isopropyl, t-butyl, hydroxyethyl, methoxyethyl, cyanoethyl,trifluoromethyl, cyclohexyl, benzyl, 2-phenethyl, vinyl, and allyl.

[0061] In the specification and claims of this application, the term“aromatic group” means an aryl group and a substituted aryl group. Thearyl group is preferably phenyl or naphthyl, and particularly preferablyphenyl. The aromatic group preferably has from 6 to 20 carbon atoms, andmore preferably from 6 to 16 carbon atoms.

[0062] Examples of the aromatic group include phenyl, p-tolyl,p-methoxyphenyl, and p-chlorophenyl.

[0063] The heterocyclic group includes a substituted heterocyclic groupand an unsubstituted heterocyclic group. The heterocyclic ring may becondensed with an aliphatic ring, an aromatic ring, or otherheterocyclic ring. As the heterocyclic group, a 5- or 6-memberedheterocyclic group is preferred. Examples of the substituent include analiphatic group, a halogen atom, an alkyl- or arylsulfonyl group, anacyl group, an acylamino group, a sulfamoyl group, and a carbamoylgroup.

[0064] Examples of the heterocyclic group include a 2-pyridyl group, a2-thienyl group, a 2-thiazolyl group, a 2-benzothiazolyl group, a2-benzoxazolyl group, and a 2-furyl group.

[0065] The alkyl- or arylsulfonyl group includes a substituted alkyl- orarylsulfonyl group and an unsubstituted alkyl- or arylsulfonyl group.Examples of the alkyl- or arylsulfonyl group include a methanesulfonylgroup and a phenylsulfonyl group.

[0066] The alkyl- or arylsulfinyl group includes a substituted alkyl- orarylsulfinyl group and an unsubstituted alkyl- or arylsulfinyl group.Examples of the alkyl- or arylsulfinyl group include a methanesulfinylgroup and a phenylsulfinyl group.

[0067] The acyl group includes a substituted acyl group and anunsubstituted acyl group. The acyl group preferably has from 1 to 12carbon atoms. Examples of the acyl group include an acetyl group and abenzoyl group.

[0068] Examples of the halogen atom include a fluorine atom, a chlorineatom, and a bromine atom.

[0069] The amino group substituted with an alkyl group, an aryl group ora heterocyclic group include an amino group substituted with one or twogroups selected from an alkyl group, an aryl group, and a heterocyclicgroup. Each of the alkyl group, the aryl group, and the heterocyclicgroup may further have a substituent. An unsubstituted amino group isnot included. As the alkylamino group, an alkyamino group having from 1to 6 carbon atoms is preferred. Examples of the alkylamino group includea methylamino group and a diethylamino group.

[0070] The arylamino group includes a substituted arylamino group and anunsubstituted arylamino group. As the arylamino group, an arylaminogroup having from 6 to 12 carbon atoms is preferred. Examples of thesubstituent include a halogen atom.

[0071] Examples of the arylamino group include an anilino group and a2-chloroanilino group.

[0072] The alkoxy group includes a substituted alkoxy group and anunsubstituted alkoxy group. As the alkoxy group, an alkoxy group havingfrom 1 to 12 carbon atoms is preferred. Examples of the substituentinclude an alkoxy group and a hydroxyl group. Examples of the alkoxygroup include a methoxy group, an ethoxy group, an isopropoxy group, amethoxyethoxy group, and a hydroxyethoxy group.

[0073] The aryloxy group includes a substituted aryloxy group and anunsubstituted aryloxy group. As the aryloxy group, an aryloxy grouphaving from 6 to 12 carbon atoms is preferred. Examples of thesubstituent include an alkoxy group. Examples of the aryloxy groupinclude a phenoxy group, a p-methoxyphenoxy group, and ano-methoxyphenoxy group.

[0074] As the silyloxy group, an aliphatic group- or aromaticgroup-substituted silyloxy group having from 1 to 12 carbon atoms ispreferred. Examples of the silyloxy group include trimethylsilyloxy anddiphenylmethylsilyloxy.

[0075] The heterocyclic oxy group includes a substituted heterocyclicoxy group and an unsubstituted heterocyclic oxy group. As theheterocyclic oxy group, a heterocyclic oxy group having from 2 to 12carbon atoms is preferred. Examples of the substituent include an alkylgroup and an alkoxy group. Examples of the heterocyclic oxy groupinclude a 3-pyridyloxy group and a 3-thienyloxy group.

[0076] The alkoxycarbonyloxy group includes a substitutedalkoxycarbonyloxy group and an unsubstituted alkoxycarbonyloxy group. Asthe alkoxycarbonyloxy group, an alkoxycarbonyloxy group having from 2 to12 carbon atoms is preferred. Examples of the alkoxycarbonyloxy groupinclude a methoxycarbonyloxy group and an isopropoxycarbonyloxy group.

[0077] The aryloxycarbonyloxy group includes a substitutedaryloxycarbonyloxy group and an unsubstituted aryloxycarbonyloxy group.As the aryloxycarbonyloxy group, an aryloxycarbonyloxy group having from7 to 12 carbon atoms is preferred. Examples of the aryloxycarbonyloxygroup include a phenoxycarbonyloxy group.

[0078] The acylamino group includes a substituted-acylamino group andan, unsubstituted acylamino group. As the acylamino group, an acylaminogroup having from 2 to 12 carbon atoms is preferred. Examples of theacylamino group include an acetylamino group, a propionylamino group, abenzoylamino group, and an N-phenylacetylamino group.

[0079] The ureido group includes a substituted ureido group and anunsubstituted ureido group. As the ureido group, a ureido group havingfrom 1 to 12 carbon atoms is preferred. Examples of the substituentinclude an alkyl group and an aryl group. Examples of the ureido groupinclude a 3-methylureido group, a 3,3-dimethylureido group, and a3-phenylureido group.

[0080] The sulfamoylamino group includes a substituted sulfamoylaminogroup and an unsubstituted sulfamoylamino group. Examples of thesubstituent include an alkyl group. Examples of the sulfamoylamino groupinclude an N,N-dipropylsulfamoylamino group.

[0081] The alkoxycarbonylamino group includes a substitutedalkoxycarbonylamino group and an unsubstituted alkoxycarbonylaminogroup. As the alkoxycarbonylamino group, an alkoxycarbonylamino grouphaving from 2 to 12 carbon atoms is preferred. Examples of thealkoxycarbonylamino group include an ethoxycarbonylamino group.

[0082] The alkyl- or arylsulfonylamino group includes a substitutedalkyl- or arylsulfonylamino group and an unsubstituted alkyl- gorearylsulfonylamino group. As the alkyl or arylsulfonylamino groups analkyl- or arylsulfonylamino group having from 1 to 12 carbon atoms ispreferred. Examples of the alkyl- or arylsulfonylamino group include amethanesulfonylamino group, an N-phenylmethanesulfonylamino group, and abenzenesulfonylamino group.

[0083] The carbamoyl group includes a substituted carbamoyl group and anunsubstituted carbamoyl group. Examples of the substituent include analkyl group. Examples of the carbamoyl group include a methylcarbamoylgroup and a dimethylcarbamoyl group.

[0084] The sulfamoyl group includes a substituted sulfamoyl group and anunsubstituted sulfamoyl group. Examples of the substituent include analkyl group. Examples of the sulfamoyl group include a dimethylsulfamoylgroup and a di- (2-hydroxyethyl)sulfamoyl group.

[0085] The alkoxycarbonyl group includes a substituted alkoxycarbonylgroup and an unsubstituted alkoxycarbonyl group. As the alkoxycarbonylgroup, an alkoxycarbonyl group having from 2 to 12 carbon atoms ispreferred. Examples of the alkoxycarbonyl group include amethoxycarbonyl group and an ethoxycarbonyl group.

[0086] The acyloxy group includes a substituted acyloxy group and anunsubstituted acyloxy group. As the acyloxy group, an acyloxy grouphaving from 1 to 12 carbon atoms is preferred. Examples of the acyloxygroup include an. acetoxy group and a benzoyloxy group.

[0087] The carbamoyloxy group includes a substituted carbamoyloxy groupand an unsubstituted carbamoyloxy group. Examples of the substituentinclude an alkyl group. Examples of the carbamoyloxy group include anN-methylcarbamoyloxy group.

[0088] The aryloxycarbonyl group includes a substituted aryloxycarbonylgroup and an unsubstituted aryloxycarbonyl group. As the aryloxycarbonylgroup, an aryloxycarbonyl group having from 7 to 12 carbon atoms ispreferred. Examples of the aryloxycarbonyl group include aphenoxycarbonyl group.

[0089] The aryloxycarbonylamino group includes a substitutedaryloxycarbonylamino group and an unsubstituted aryloxycarbonylaminogroup. As the aryloxycarbonylamino group, an aryloxycarbonylamino grouphaving from 7 to 12 carbon atoms is preferred. Examples of thearyloxycarbonylamino group include a phenoxycarbonylamino group.

[0090] The alkyl-, aryl- or heterocyclic thio group includes asubstituted alkyl-, aryl- or heterocyclic thio group and anunsubstituted alkyl-, aryl- or heterocyclic thio group. As the alkyl-,aryl- or heterocyclic thio group, an alkyl-, aryl- or heterocyclic thiogroup having from 1 to 12 carbon atoms is preferred. Examples of thealkyl-, aryl- or heterocyclic thio group include a methylthio group, aphenylthio group, and a 2-pyridylthio group.

[0091] The heterocyclic oxycarbonyl group includes a substitutedheterocyclic oxycarbonyl group and an unsubstituted heterocyclicoxycarbonyl group. As the heterocyclic oxycarbonyl group, a heterocyclicoxycarbonyl group having from 2 to 12 carbon atoms is preferred.Examples of the heterocyclic oxycarbonyl group include a2-pyridyloxycarbonyl group.

[0092] The heterocyclic -sulfonylamino group includes a substitutedheterocyclic sulfonylamino group and an unsubstituted heterocyclicsulfonylamino group. As the heterocyclic sulfonylamino group, aheterocyclic sulfonylamino group having from 1 to 12 carbon atoms ispreferred. Examples of the heterocyclic sulfonylamino group include a2-thiophenesulfonylamino group and a 3-pyridinesulfonylamino group.

[0093] The heterocyclic sulfonyl group includes a substitutedheterocyclic sulfonyl group and an unsubstituted heterocyclic sulfonylgroup. As the heterocyclic sulfonyl group, a heterocyclic sulfonyl grouphaving from 1 to 12 carbon is preferred. Examples of the heterocyclicsulfonyl group include a 2-thiophenesulfonyl group and a3-pyridinesulfonyl group.

[0094] The heterocyclic sulfinyl group includes a substitutedheterocyclic sulfinyl. group and an unsubstituted heterocyclic sulfonylgroup. As the heterocyclic sulfonyl group, a heterocyclic sulfinyl grouphaving from 1 to 12 carbon is preferred. Examples of the heterocyclicsulfinyl group include a 4-pyridinesulfinyl group.

[0095] In the present invention, ones represented by the followinggeneral formula (I-la) are a particularly preferred structure.

[0096] In the general formula (I-1a), Z¹ represents an electronattractive group having a Hammett's substituent constant, op value of0.20 or more. Z¹ preferably represents an electron attractive grouphaving a σp value of 0.30 or more, more preferably an electronattractive group having a σp value of 0.45 or more, and most preferablyan electron attractive group having a σp value of 0.60 or more. However,it is desired that the σp value does not exceed 1.0. As preferredspecific examples of the substituent, electron attractive substituentsas described later are enumerated. Especially, an acyl group having from2 to 12 carbon atoms, an alkyloxycarbonyl group having from 2 to 12carbon atoms, a nitro group, a cyano group, an alkylsulfonyl grouphaving from 1 to 12 carbon atoms, an arylsulfonyl group having from 6 to18 carbon atoms, a carbamoyl group having from 1 to 12 carbon atoms, anda. halogenated alkyl group having from 1 to 12 carbon atoms arepreferred. Of these are particularly preferable a cyano group, analkylsulfonyl group having from 1 to 12 carbon atoms, and anarylsulfonyl group having from 6 to 18 carbon atoms, with a cyano groupbeing most preferred.

[0097] Z² represents a hydrogen atom, an aliphatic group, an aromaticgroup, or a heterocyclic group.

[0098] Z³ represents a hydrogen atom, an aliphatic group, an aromaticgroup, or a heterocyclic group. Especially, it is preferred that Z³represents a group comprising a non-metal atomic group necessary forforming a 5- to 8-membered ring.

[0099] The 5- to 8-membered ring may be substituted or may be asaturated ring, or may have an unsaturated bond. Among them, an aromaticgroup and a heterocyclic group are particularly preferred. As thenon-metal atom are preferable a nitrogen atom, an oxygen atom, a sulfuratom, and a carbon atom. Specific examples of such ring structuresinclude a benzene ring, a cyclopentane ring, a cyclohexane ring, acycloheptane ring, a cyclooctane ring, a cyclohexene ring, a pyridinering, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazinering, an imidazole ring, a benzoimidazole ring, an oxazole ring, abenzoxazole ring, a thiazole ring, a benzothiazole ring, an oxane ring,a sulfolane ring, and a thiane ring.

[0100] R¹, R², R⁵; and R⁶ are synonymous with those in the generalformula (I-1).

[0101] R⁴¹ and R⁴² each independently represents a hydrogen atom or asubstituent. Examples of the substituent include an aliphatic group, anaromatic group, a heterocyclic group, an acyl group, an alkoxycarbonylgroup, an aryloxycarbonyl group, a carbamoyl group, an alkyl- orarylsulfonyl group, and a sulfamoyl group. Of these are preferable ahydrogen atom, an aromatic group, a heterocyclic group, an acyl group,and an alkyl- or arylsulfonyl group, with a hydrogen atom, an aromaticgroup, and a heterocyclic group being particularly preferred.

[0102] Each of the groups described for the general formula (I-1a) mayfurther have a substituent. In the case where each of these groups has asubstituent, examples of the substituent include those described for thegeneral formula (I-1) and those enumerated for R¹, R², and R⁴.

[0103] Now, the Hammett's substituent constant, σp value as referred toin the specification and claims of this application will be described.The Hammett's rule is an empirical rule advocated by L. P. Hammett in1935 in order to quantitatively discuss the influence of substituents onthe reaction or equilibrium of benzene derivatives, and propriety ofthis rule is now widely recognized. The substituent constant requiredfor the Hammett's rule includes a σp value and a σm value. These valuescan be found in many general books. For example, the details are givenin J. A. Dean ed., Lange's Handbook of Chemistry, 12th Ed. (1979), byMcGraw-Hill; and a special issue of Kagaku no Ryoiki (Regions ofChemistry), No. 122, pp.96-103 (1979), by Nankodo. Needless to say,while in the present invention, each substituent will be limited ordescribed in terms of the Hammett's substituent constant σp value, thisdoes not mean that the present invention is limited only to substituentshaving known values that can be found from the foregoing books, but thepresent invention also includes substituents, values of which areunknown but will fall within the intended scope when measured accordingto the Hammett's rule. Further, though compounds that are not a benzenederivative are included within the scopes of the general formulae (I-1)and (I-1a), the σp values are used as a measure to exhibit theelectronic effect of the substituent irrespective of the substitutionposition. In the present invention, the σp value is used in suchmeanings.

[0104] Examples of the electron attractive group having a Hammett'ssubstituent constant, σp value of 0.60 or more include a cyano group, anitro group, an alkylsulfonyl group (such as a methanesulfonyl group),and an arylsulfonyl group (such as a benzenesulfonyl group).

[0105] Examples of the electron attractive group having a Hammett'ssubstituent constant, σp value of 0.45 or,more include not only those asenumerated above but also an acyl group (such as an acetyl group), analkoxycarbonyl group (such as a dodecyloxycarbonyl group), anaryloxycarbonyl group (such as an m-chlorophenoxycarbonyl group), analkylsulfinyl group (such as an n-propylsulfinyl group), an arylsulfinylgroup (such as a phenylsulfinyl group), a sulfamoyl group (such as anN-ethylsulfamoyl group and an N,N-dimethylsulfamoyl group), and ahalogenated alkyl group (such as a trifluoromethyl group).

[0106] Examples of the electron attractive group having a Hammett'ssubstituent constant, σp value of 0.30 or more include not only those asenumerated above but also an acyloxy group (such as an acetoxy group) ,a carbamoyl group (such as an N-ethylcarbamoyl group and anN,N-dibutylcarbamoyl group), a halogenated alkoxy group (such as atrifluoromethyloxy group), a halogenated aryloxy group (such as apentafluorophenyloxy group), a sulfonyloxy group (such as amethylsulfonyloxy group), a halogenated alkylthio group (such as adifluoromethylthio group), an aryl group substituted with two or moreelectron attractive groups having a σp value of 0.15 or more (such as a2,4-dinitrophenyl group and a pentachlorophenyl group), and aheterocyclic group (such as a 2-benzoxazolyl group, a 2-benzothiazolylgroup, and a 1-phenyl-2-benzimidazolyl group). Specific examples of theelectron attractive group having a σp value of 0.20 or more include notonly those as enumerated above but also a halogen atom.

[0107] With respect to the particularly preferred combination ofsubstituents as the azo dye represented by the general formula (I-1) ,R¹ and R² are each preferably a hydrogen atom, a halogen atom, a cyanogroup, a carbamoyl group, an alkyl group, a hydroxyl group, or an alkoxygroup, and more preferably a hydrogen atom, a cyano group, a carbamoylgroup, or an alkoxy group.

[0108] R⁴ is preferably a hydrogen atom, a halogen atom, an alkyl group,a hydroxyl group, an amino group, or an amide group, more preferably ahydrogen atom, a halogen atom, an amino group, or an amide group, andmost preferably a hydrogen atom, an amino group, or an amide group.

[0109] D is preferably a pyrazole ring, an imidazole ring, anisothiazole ring, a thiadiazole ring, or a benzothiazole ring, morepreferably a pyrazole ring or an isothiazole ring, and most preferably apyrazole ring.

[0110] R⁵ and R⁶ are each preferably a hydrogen atom, an aryl group, ora heterocyclic group. Preferably, R⁵ and R⁶ do not represent a hydrogenatom at the same time.

[0111] With respect to the preferred combination of substituentsrepresented by the general formula (I-1), compounds in which at leastone of the various substituents represents a substituent as enumeratedabove as the preferred examples are preferable; compounds in which manyof the various substituents represent substituents as enumerated aboveas the preferred examples are more preferable; and compounds in whichall of the substituents represent substituents as enumerated above asthe preferred examples are most preferable.

[0112] Specific examples of the azo dye represented by the generalformula (I-1) will be given below, but it should not be construed thatthe azo dye to be used in the present invention is limited thereto.

Dye R1 R2 R3 a-1

a-2

a-3

a-4

a-5

a-6

a-7

a-8

a-9

C₈H₁₇(t) a-10

Dye R₁ R₂ R₃ R₄ a-11

a-12

a-13

a-14

(4,5-mix)

a-15

Dye R₁ R₂ R₃ R₄ a-16

a-17

—SO₂CH₃

a-18

—COCH₃ C₈H₁₇(t) C₈H₁₇(t) a-19

a-20

—SO₂CH₃

C₈H₁₇(t) a-21

a-22

a-23

a-24

a-25

C₈H₁₇(t)

Dye R₁ R₂ R₃ R₄ R₅ R₆ R₇ R₈ a-30

CN

H CONH₂ SO₂CH₃

a-31

Br

COOEt H

C₈H₁₇(t) COCH₃ a-32

SO₂CH₃

CONH₂ H

a-33

CN

H H

SO₂CH₃ a-34

Br

H CONH₂

a-35

CN

CH₃ H

a-36

CN

CH₃ CN H

Dye R₁ R₂ R₃ R₄ R₅ R₆ b-1 CH₃ CH₃ CN H

b-2 CH₃ CH₃ CN H

b-3 CH₃ CH₃ CONH₂ H

b-4 CH₃ CH₃ H H

b-5 CH₃ H CN H

b-6 CH₃ CH₃ H

b-7 CH₃ CH₃ H

b-8 CH₃ H H SO₂CH₃

Dye R₁ R₂ R₃ R₄ R₅ R₆ c-1 —SCH₃ CH₃ CN H C₈H₁₇(t)

c-2

H CONH₂ H

c-3

CH₃ H

c-4 —CH₃ CH₃ H

c-5

H H

C₈H₁₇(t)

Dye R₁ R₃ R₃ R₄ R₅ R₆ d-1 Me CH₃ CN H

d-2 Me CH₃ CN H

d-3 Me H H

d-4 Ph CH₃ CONH₂ H

d-5 Ph CH₃ H

Dye R₁ R₂ R₃ R₄ R₅ R₆ e-1 5-Cl CH₃ CONH₂ H C₈H₁₇(t) C₈H₁₇(t) e-25,6-diCl H H

e-3 5,6-diCl CH₃ H

COCH₃ e-4 5-CH₃ H CN H

e-5 5-NO₂ CH₃ H SO₂CH₃

[0113] As the cyan dye of the oil-soluble dyes that can be used in thepresent invention, arbitrary cyan dyes can be used. As the cyan dye canbe enumerated indoaniline dyes; indophenol dyes; azo methine dyes havinga pyrrolotriazole as a coupling component; polymethine dyes such ascyanine dyes, oxonol dyes, and merocyanine dyes; carbonium dyes such asdiphenylmethane dyes, triphenylmethane dyes, and xanthene dyes;phthalocyanine dyes; anthraquinone dyes; aryl or heteryl azo dyeshaving, for example, a phenol, a naphthol, or an aniline as a couplingcomponent; indigo dyes; and thioindigo dyes.

[0114] Especially, oil-soluble dyes represented by the general formula(A-I) are preferably used.

[0115] In the general formula (A-I) , X₁, X₂, X₃, and X₄ eachindependently represents a group selected from —SO—Z, —SO₂—Z —SO₂NR₁R₂,—CONR₁R₂, —CO₂R₁, and a sulfo group.

[0116] Zs′ each independently represents a substituted or unsubstitutedalkyl group, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted aryl group,or a substituted or unsubstituted heterocyclic group; preferably asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaryl group, or a substituted or unsubstituted heterocyclic group; andmost preferably a substituted alkyl group, a substituted aryl group, orsubstituted a heterocyclic group. It is preferred that X₁, X₂, X₃, andX₄ each represents —SO₂—Z or —SO₂NR₁R₂.

[0117] R₁ and R₂ each independently represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedcycloalkyl group, a substituted or unsubstituted alkenyl group, asubstituted or unsubstituted aralkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted heterocyclicgroup; preferably a hydrogen atom, a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group; and most preferably a hydrogen atom, asubstituted alkyl group, a substituted aryl group, or a substitutedheterocyclic group. However, R₁ and R₂ do not represent a hydrogen atomat the same time.

[0118] As specific examples of the substituted or unsubstituted alkylgroup, cycloalkyl group, alkenyl group and aryl group are enumeratedthose as described in the later section (specific examples ofsubstituent).

[0119] As the heterocyclic group represented by R₁, R₂, and Z, a 5- or6-membered heterocyclic ring is preferred. The heterocyclic ring may befurther condensed. Further, the heterocyclic ring may be an aromaticheterocyclic ring or a non-aromatic heterocyclic ring. Specific examplesof the heterocyclic group represented by R₁, R₂, and Z will be givenbelow in terms of the form of a heterocyclic ring while omitting thesubstitution position or positions, but it should be construed that thesubstitution position or positions are never limited thereto. Forexample, in the case of a pyridine, it can be substituted at the2-position, 3-position or 4-position.

[0120] (Specific examples of heterocyclic group)

[0121] Pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline,isoquinoline, quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole,indole, furan, benzofuran, thiophene, benzothiophene, pyrazole,imidazole, benzimidazole, triazole, oxazole, benzoxazole, thiazole,benzothiazole, isothiazole, benzisothiazole, thiadiazole, isoxazole,benzisoxazole, pyrrolidine, piperidine, piperazine, imidazoline, andthiazoline.

[0122] Of these, aromatic heterocyclic groups are preferred. Specificexamples of the aromatic heterocyclic group include pyridine, pyrazine,pyrimidine, pyridazine, triazine, pyrazole, imidazole, benzimidazole,triazole, thiazole, benzothiazole, isothiazole, benzisothiazole, andthiadiazole. Each of these groups may further have a substituent asdescribed later.

[0123] Y₁, Y₂, Y₃, and Y₄ each independently represents a hydrogen atomor a monovalent substituent. Examples of the monovalent substituentrepresented by Y₁, Y₂, Y₃, and Y₄ include a halogen atom, an alkylgroup, a cycloalkyl group, an alkenyl group, an aralkyl group, an arylgroup, a heterocyclic group, a cyano group, a hydroxyl group, a nitrogroup, an amino group, an alkylamino group, an alkoxy group, an aryloxygroup, an amide group, an arylamino group, a ureido group, asulfamoylamino group, an alkylthio group, an arylthio group, analkoxycarbonylamino group, a sulfonamide group, a carbamoyl group, asulfamoyl group, a sulfonyl group, an alkoxycarbonyl group, aheterocyclic oxy group, an azo group, an acyloxy group, a carbamoyloxygroup, a silyloxy group, an aryloxycarbonyl group, anaryloxycarbonylamino group, an imido group, a heterocyclic thio group, aphosphoryl group, an acyl group, a carboxyl group, and a sulfo group.Each of these groups may further have a substituent.

[0124] Especially, Y₁, Y₂, Y₃, and Y4 are each preferably a hydrogenatom, a halogen atom, an alkyl group, an aryl group, a cyano group, analkoxy group, an amide group, a ureid group, a sulfonamide group, acarbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, a carboxylgroup, or a sulfo group; more preferably a hydrogen atom, a halogenatom, a cyano group, a carboxyl group, or a sulfo group; and mostpreferably a hydrogen atom.

[0125] When Z, R₁, R₂, Y₁, Y₂, Y₃, and Y₄ each represents a group thatcan further have a substituent, these groups may have the followingsubstituents.

[0126] (Specific examples of substituent)

[0127] A halogen atom (such as a chlorine atom and a bromine atom); alinear or branched chain alkyl group having from 1 to 12 carbon atoms,an aralkyl group having from 7 to 18 carbon atoms, an alkenyl grouphaving from 2 to 12 carbon atoms, a linear or branched chain alkenylgroup having from 2 to 12 carbon atoms, a linear or branched chainalkinyl group having from 2 to 12 carbon atoms, a linear or branched-chain cycloalkyl group having from 3 to 12 carbon atoms, and a linear orbranched chain cycloalkenyl group having from 3 to 12 carbon atoms (suchas methyl, ethyl, propyl, isopropyl, t-butyl, 2-methanesulfonylethyl,3-phenoxypropyl, trifluoromethyl, and cyclopentyl); an aryl group (suchas phenyl, 4-t-butylphenyl, 2,4-di-t-amylphenyl); a heterocyclic group(such as imidazolyl, pyrazolyl, triazolyl, 2-furyl, 2-thienyl,2-pyrimidinyl, and 2-benzothiazolyl); a cyano group; a hydroxyl group; anitro group; a carboxy group; an amino group; an alkyloxy group (such asmethoxy, ethoxy, 2-methoxyethoxy, and 2-methanesulfonylethoxy); anaryloxy group (such as phenoxy, 2-methylphenoxy, 4-t-butylphenoxy,3-nitrophenoxy, 3-t-butyloxycarbamoylphenoxy, and 3-methoxycarbamoyl);an acylamino group (such as acetamide, benzamide, and4-(3-t-butyl-4-hydroxyphenoxy)butanamide); an alkylamino group (such asmethylamino, butylamino, diethylamino, and methylbutylamino); an anilinogroup (such as phenylamino and 2-chloroanilino); a ureido group (such asphenylureido, methylureido, and N,N-dibutylureido); a sulfamoylaminogroup (such as N,N-dipropylsulfamoylamino); an alkylthio group (such asmethylthio, octylthio, and 2-phenoxyethylthio); an arylthio group (suchas phenylthio, 2-butoxy-5-t-octylphenylthio, and 2-carboxyphenylthio);an alkyloxycarbonylamino group (such as methoxycarbonylamino); asulfonamide group (such as methanesulfonamide, benzenesulfonamide, andp-toluenesulfonamide); a carbamoyl group (such as N-ethylcarbamoyl andN,N-dibutylcarbamoyl); a sulfamoyl group (such as N-ethylsulfamoyl,N,N-dipropylsulfamoyl, and N-phenylsulfamoyl); a sulfonyl group (such asmethanesulfonyl, octanesulfonyl, benzenesulfonyl, and toluenesulfonyl);an alkyloxycarbonyl group (such as methoxycarbonyl andbutyloxycarbonyl); a heterocyclic oxy group (such as1-phenyltetrazole-5-oxy and 2-tetrahydropyranyloxy); an azo group (suchas phenylazo, 4-methoxyphenylazo, 4-pivaroylaminophenylazo, and2-hydroxy-4-propanoylphenylazo); an acyloxy group (such as acetoxy); acarbamoyloxy group (such as N-methylcarbamoyloxy andN-phenylcarbamoyloxy); a silyloxy group (such as trimethylsilyloxy anddibutylmethylsilyloxy); an aryloxycarbonylamino group. (such asphenoxycarbonylamino); an imido group (such as N-succimido andN-phthalimido); a heterocyclic thio group (such as 2-benzothiazolylthio,2,4-diphenoxy-1,3,5-triazole-6-thio, and 2-pyridylthio); a sulfinylgroup (such as 3-phenoxypropylsulfinyl); a phosphonyl group (such asphenoxyphosphonyl, octyloxyphosphonyl, and phenylphosphonyl); anaryloxycarbonyl group (such as phenoxycarbonyl); an acyl group (such asacetyl, 3-phenylpropanoyl, and benzoyl); and an ionic hydrophilic group(such as a carboxyl group, a sulfo group, and a quaternary ammoniumgroup).

[0128]a₁ to a₄ and b₁ to b₄ represent the numbers of X₁ to X₄ and Y₁ toY₄, respectively and each independently represents an integer of from 0to 4.

[0129] As a matter of course from the previously described definition,a₁ and b₁ each independently represents an integer of from 0 to 4 whilemeeting the relationship of (a₁+b₁)=4. However; the total sum of a₁ toa₄ is 2 or more and 16 or less. Especially, a combination in which a₁ is1 or 2, and b₁ is 3 or 2 is preferred, with a combination of a₁ =1 andb₁ =3 is most preferred.

[0130] In each of the combinations of a₂ and b₂ , a₃ and b₃ , and a₄ andb₄ , there is the same relationship as in the case of the combination ofa₁ and b₁ , and a preferred combination is also the same.

[0131] M represents a hydrogen atom, a metal element, a metal oxide, ametal hydroxide, or a metal halide.

[0132] As preferred examples of M are enumerated a hydrogen atom; Li,Na, K, Mg, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Ru, Rh, Pd, Os,Ir, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Si, Ge, Sn, Pb, Sb, and Bias the metal element; VO and GeO as the metal oxide; Si(OH)₂, Cr(OH)₂,and Sn(OH)₂ as the metal hydroxide; and AlCl, SiCl₂, VCl, VCl₂, VOCl,FeCl, GaCl, and ZrCl as the metal halide.

[0133] Among them, Cu, Ni, Zn, and Al are more preferred, with Cu beingmost preferred.

[0134] Further, Pc (phthalocyanine ring) may form a dimer (such asPc-M-L-M-Pc) or a trimer via L (divalent connecting group). At thattime, Ms′ may be the same or different from each other.

[0135] As the divalent connecting group represented by L are preferablean oxy group (—O—) a thio group (—S—), a carbonyl group (—CO—), asulfonyl group (—SO₂—), an imino group (—NH—), and a methylene group(—CH₂—).

[0136] As the oil-soluble dye represented by the general formula (A-I)are especially preferable the following combinations.

[0137] Particularly preferably, X₁ to X₄ each independently represents—SO₂—Z or —SO₂NR₁R₂.

[0138] Preferably, Zs′ each independently represents a substituted orunsubstituted alkyl group, a substituted or unsubstituted aryl group, ora substituted or unsubstituted heterocyclic group, and most preferably asubstituted alkyl group, a substituted aryl group, or a substitutedheterocyclic group.

[0139] Preferably, R₁ and R₂ each independently represents a hydrogenatom, a substituted or unsubstituted alkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted heterocyclicgroup, and most preferably a hydrogen atom, a substituted alkyl group, asubstituted aryl group, or a substituted heterocyclic group.

[0140] Preferably, Y₁ to Y₄ each independently represents a hydrogenatom, a halogen atom, an alkyl group, an aryl group, a cyano group, analkoxy group, an amide group, a ureido group, a sulfonamide .group, acarbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, a carboxylgroup, or a sulfo group, and more preferably a hydrogen atom, a halogenatom, a cyano group, a carboxyl group, or a sulfo group, with the casewhere all of Y₁ to Y₄ are a hydrogen atom being most preferred.

[0141] Preferably, a₁ to a₄ each independently represents 1 or 2, andmost preferably 1. Preferably, b₁ to b₄ each independently represents 3or 2, and most preferably 3.

[0142] Preferably, M represents a hydrogen atom, a metal element, ametal oxide, a metal hydroxide, or a metal halide, more preferably Cu,Ni, Zn, or Al, and most preferably Cu.

[0143] Preferably, the oil-soluble dye represented by the generalformula (A-I) contains an ionic hydrophilic group. More preferably, theoil-soluble dye has at least four ionic hydrophilic groups in onemolecule thereof. Especially, it is preferred that the ionic hydrophilicgroup is a sulfo group. Most preferably, the oil-soluble dye has atleast four sulfo groups.

[0144] With respect to the preferred combination of groups of thecompound represented by the general formula (A-I), compounds in which atleast one of the various groups represents a substituent as enumeratedabove as the preferred examples are preferable; compounds in which manyof the various groups represent substituents as enumerated above as thepreferred examples are more preferable; and compounds in which all ofthe groups represent substituents as enumerated above as the preferredexamples are most preferable.

[0145] Of the oil-soluble dyes represented by the general; formula (A-I)is more preferable an oil-soluble dye-having a structure represented bythe following general formula (A-II). The oil-soluble dye represented bythe general formula (A-II) of the present invention will be describedbelow in detail.

[0146] In the general formula (A-II) , X₁₁ to X₁₄ and Y₁₁ to Y₁₈ aresynonymous with X₁ to X₄ and Y₁ to Y₄ in the general formula (A-I), andtheirpreferred examples are also the same. Further, M is synonymous withM in the general formula (I), and its preferred examples are also thesame.

[0147] In the general formula (A-II), a₁₁ to a₁₄ each independentlyrepresents an integer of 1 or 2, and preferably, they meet therelationship of 4≦(a₁₁+a₁₂+a₁₃+a₁₄) ≦6, with the case ofa₁₁=a₁₂=a₁₃=a₁₄=1 being most preferred.

[0148] As the oil-soluble dye represented by the general formula (A-II)are especially preferable the following combinations.

[0149] Particularly preferably, X₁₁ to X₁₄ each independently represents—SO₂—Z or —SO₂NR₁R₂.

[0150] Preferably, Zs′ each independently represents a substituted orunsubstituted alkyl group, a substituted or unsubstituted aryl group, ora substituted or unsubstituted heterocyclic group, and most preferably asubstituted alkyl group, a substituted aryl group, or a substitutedheterocyclic group.

[0151] Preferably, R₁ and R₂ each independently represents a hydrogenatom, a substituted or unsubstituted alkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted heterocyclicgroup, and most preferably a hydrogen atom, a substituted alkyl group, asubstituted aryl group, or a substituted heterocyclic group. However, R₁and R₂ do not represent a hydrogen atom at the same time.

[0152] Preferably, Y₁₁ to Y₁₈ each independently represents a hydrogenatom, a halogen atom, an alkyl group, an aryl group, a cyano group, analkoxy group, an amide group, a ureido group, a sulfonamide group, acarbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, a carboxylgroup, or a sulfo group, more preferably a hydrogen atom, a halogenatom, a cyano group, a carboxyl group, or a sulfo group, and mostpreferably a hydrogen atom.

[0153] Preferably, a₁₁ to a₁₄ each independently represents 1 or 2, withthe case where all of a₁₁ to a₁₄ are 1 being most preferred.

[0154] Preferably, M represents a hydrogen atom, a metal element, ametal oxide, a metal hydroxide, or a metal halide, more preferably Cu,Ni, Zn, or Al, and most preferably Cu.

[0155] In the case where the oil-soluble dye represented by the generalformula (A-II) contains an ionic hydrophilic group, it is more preferredthat the oil-soluble dye has at least four ionic hydrophilic groups inone molecule thereof. Examples of the ionic hydrophilic group as thesubstituent include a sulfo group, a phosphono group, a carboxyl group,and a quaternary ammonium group. The carboxyl group and the sulfo groupmay be in the form of a salt, and examples of a counter ion to form thesalt include an alkali metal ion (such as a sodium ion and a potassiumion) and an organic cation (such as a tetramethylguanidium ion). Ofthese are preferable a sulfo group and a carboxyl group. It is mostpreferred that the ionic hydrophilic group is a sulfo group.

[0156] With respect to the preferred combination of groups of thecompound represented by the general formula (A-II) compounds in which atleast one of the various groups represents a substituent as enumeratedabove as the preferred examples are preferable; compounds in which manyof the various groups represent substituents as enumerated above as thepreferred examples are more preferable; and compounds in which all ofthe groups represent substituents as enumerated above as the preferredexamples are most preferable.

[0157] It is preferred to introduce at least one of each of electronattractive groups including a sulfinyl group, a sulfonyl group, and asulfamoyl group into each of the benzene rings of the phthalocyaninesuch that the total sum of up values is 1.6 or more.

[0158] Specific examples of the oil-soluble dyes represented by thegeneral formulae (A-I) and (A-II) (Illustrative Compounds AI-1 to AI-3and AII-1 to AII-28) will be given below, but it should not be construedthat the oil-soluble cyan dyes that are used in the present inventionare limited to these specific examples.

[0159] The following compounds are corresponding to the general formula(A-II).

Compound No. M X a AII-1 Cu

1 AII-2 Cu

1 AII-3 Cu

1 AII-4 Cu

1 AII-5 Cu

1 AII-6 Cu

1 AII-7 Cu

1 AII-8 Cu —SO₂N(CH₂CH₂OC₂H₅)₂ 1 AII-9 Cu

1 AII-10 Cu

1 AII-11 Cu —SO₂—CH₂CO₂C₂H₅ 1 AII-12 Cu

1 AII-13 Cu —SO₂—CH₂CH₂CO₂C₆H₁₃(n) 1 AII-14 Cu —SO₂—C₄H₉(n) 2 AII-15 Cu

1 AII-16 Cu

1 AII-17 Cu

1 AII-18 Cu

1 AII-19 Cu

1 AII-20 Cu

1 AII-21 Cu

1 AII-22 Cu

1 AII-23 Cu

1

[0160] In the table, specific examples of each of combinations of (₁₁,Y₁₂), (Y₁₃, Y₁₄), (Y₁₅, Y₁₆) and (Y₁₇, Y₁₈) are independently not inorder.

Compound No. M X Y₁₁, Y₁₂ Y₁₃, Y₁₄ Y₁₅, Y₁₆ Y₁₇, Y₁₈ a AII-24 Cu

H, Cl H, Cl H, Cl H, Cl 1 AII-25 Cu

H, Cl H, Cl H, Cl H, Cl 1 AII-26 Cu

H, Cl H, Cl H, Cl H, Cl 1 AII-27 Cu

Cl, Cl Cl, Cl Cl, Cl Cl, Cl 1 AII-28 Cu

H, Cl H, Cl H, Cl H, Cl 1

[0161] As the yellow dye of the oil-soluble dyes that can be used in thepresent invention, arbitrary yellow dyes can be used. As the yellow dyecan be enumerated aryl or heteryl azo dyes having, for example, aphenol, a naphthol, an aniline, a pyrazolone, a pyridone, or an openchain type active methylene compound as a coupling component; azomethine dyes having, for example, an open chain type active methylenecompound as a coupling component; methine dyes such as benzylidene dyesand monomethine oxonol dyes; and quinone-bsed dyes such asnaphthoquinone dyes and anthraquinone dyes. As other dye species can beenumerated quinophthalone dyes, nitro-nitroso dyes, acridine dyes, andacridinone dyes.

[0162] Especially, it is preferred to use an oil-soluble dye representedby the general formula (Y-I) . In the general formula (Y-I), A and Beach independently represents an optionally substituted heterocyclicgroup. As the heterocyclic ring, a heterocyclic ring constituted of a5-membered ring or a 6-membered ring is preferred. The heterocyclic ringmay be of a monocyclic structure or a polycyclic structure in which twoor more rings are condensed, and may be an aromatic heterocyclic ring ora non-aromatic heterocyclic ring. As the hetero atom constituting theheterocyclic ring are preferable a nitrogen atom, an oxygen atom, and asulfur atom.

[0163] As the heterocyclic ring represented by A are preferable5-pyrazolone, pyrazole, oxazolone, isoxazolone, barbituric acid,pyridone, rhodanine, pyrazolidinedione, pyrazolopyridone, Meldrum'sacid, and condensed heterocyclic rings of the foregoing heterocyclicrings with a hydrocarbon aromatic ring or a heterocyclic ring. Of theseare more preferable 5-pyrazolone, 5-aminopyrazole, pyridone, andpyrazoloazole, with 5-aminopyrazole, 2-hydroxy-6-pyridone, andpyrazolotriazole being particularly preferred.

[0164] As the heterocyclic ring represented by B are suitable pyridine,pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline,quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole,furan, benzofuran, thiophene, benzothiophene, pyrazole imidazole,benzimidazole, triazole, oxazole, isoxazole, benzoxazole, thiazole,benzothiazole, isothiazole, benzoisothiazole, thiadiazole,benzoisoxazole, pyrrolidine, piperidine, piperazine, imidazoline, andthiazoline. Of these, pyridine, quinoline, thiophene, benzothiophene,pyrazole, imidazole, benzimidazole, triazole, oxazole, isoxazole,benzoxazole, thiazole, benzothiazole, isothiazole, benzoisothiazole,thiadiazole, and benzoisoxazole are preferable; quinoline, thiophene,pyrazole, thiazole, benzoxazole, benzoisoxazole, isothiazole, imidazole,benzothiazole, and thiadiazole are more preferable; and pyrazole,benzothiazole, benzoxazole, imidazole, 1,2,4-thiadiazole, and1,3,4-thiadiazole are most preferable.

[0165] Examples of the substituent that is substituted on A and Binclude a halogen atom, an alkyl group, a cycloalkyl group, an aralkylgroup, an alkenyl group, an alkynyl group, an aryl group, a heterocyclicgroup, a cyano group, a hydroxyl group, a nitro group, an alkoxy group,an aryloxy group, a silyloxy group, a heterocyclic oxy group, an acyloxygroup, a carbamoyloxy group, an alkoxycarbonyloxy group, anaryloxycarbonyloxy group, an amino group, an acylamino group, anaminocarbonylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfamoylamino group, an alkyl- orarylsulfonylamino group, a mercapto group, an alkylthio group, anarylthio group, a heterocyclic thio group, a sulfamoyl group, an alkyl-or arylsulfinyl group, an alkyl- or arylsufonyl group, an acyl group, anaryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, animido group, a phosphino group, a phosphinyl group, a phosphinyloxygroup, a phosphinylamino group, and a silyl group.

[0166] Among the dyes represented by the general formula (Y-I) are morepreferable dyes represented by the following general formulae (Y-II),(Y-III) and (Y-IV).

[0167] In the general formula (Y-II), R¹ and R³ each represents ahydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, anaralkyl group, an alkoxy group, an alkylthio group, an arylthio group,an aryl group, or an ionic hydrophilic group; R² represents a hydrogenatom, an alkyl group, a cycloalkyl group, an aralkyl group, a carbamoylgroup, an acyl group, an aryl group, or a heterocyclic group; and R⁴represents a heterocyclic group.

[0168] In the general formula (Y-III), R⁵ represents a hydrogen atom, acyano group, an alkyl group, a cycloalkyl group, an aralkyl group, analkoxy group, an alkylthio group, an arylthio group, an aryl group, oran ionic hydrophilic group; Za represents —N═, —NH—, or C(R¹¹)═; Za andZc each independently represents —N═ or C(R¹¹)═; R¹¹ represents ahydrogen atom or a non-metallic substituent; and R⁶ represents aheterocyclic group.

[0169] In the general formula (Y-IV), R⁷ and R⁹ each represents ahydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, anaralkyl group, an aryl group, an alkylthio group, an arylthio group, analkoxycarbonyl group, a carbamoyl group, or an ionic hydrophilic group;R⁸ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxygroup, an aryl group, an aryloxy group, a cyano group, an acylaminogroup, a sulfonylamino group, an alkoxycarbonylamino group, a ureidogroup, an alkylthio group, an arylthio group, an alkoxycarbonyl group, acarbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, analkylamino group, an arylamino group, a hydroxyl group, or an ionichydrophilic group; and R¹⁰ represents a heterocyclic group.

[0170] In the general formula (Y-II), R¹ and R³ each represents ahydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, anaralkyl group, an alkoxy group, an alkylthio group, an arylthio group,an aryl group, or an ionic hydrophilic group; R² represents a hydrogenatom, an alkyl group, a cycloalkyl group, an aralkyl group, a carbamoylgroup, an acyl group, an aryl group, or a heterocyclic group; and R⁴represents a heterocyclic group.

[0171] In the general formula (Y-III), R⁵ represents a hydrogen atom, acyano group, an alkyl group, a cycloalkyl group, an aralkyl group, analkoxy group, an alkylthio group, an arylthio group, an aryl group, oran ionic hydrophilic group; Za represents —N═, —NH—, or C(R¹¹)═; Za andZc each independently represents —N═ or C(R¹¹)═; R¹¹ represents ahydrogen atom or a non-metallic substituent; and R⁶ represents aheterocyclic group.

[0172] In the general formula (Y-IV), R⁷ and R⁹ each represents ahydrogen atom, a cyano group, an alkyl group, a cycloalkyl group, anaralkyl group, an aryl group, an alkylthio group, an arylthio group, analkoxycarbonyl group, a carbamoyl group, or an ionic hydrophilic group;R⁸ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxygroup, an aryl group, an aryloxy group, a cyano group, an acylaminogroup, a sulfonylamino group, an alkoxycarbonylamino group, a ureidogroup, an alkylthio group, an arylthio group, an alkoxycarbonyl group, acarbamoyl group, a sulfamoyl group, a sulfonyl group, an acyl group, analkylamino group, an arylamino group, a hydroxyl group, or an ionichydrophilic group; and R¹⁰ represents a heterocyclic group.

[0173] The substituents represented by R¹, R², R³, R⁵, R⁷, R⁸, and R⁹ inthe general formulae (Y-II), (Y-III) and (Y-IV) will be described belowin detail.

[0174] The alkyl group represented by R¹, R², R³, R⁵, R⁷, R⁸, and R⁹includes a substituted alkyl group and an unsubstituted alkyl group.

[0175] As the alkyl group is preferable an alkyl group having from 1 to20 carbon atoms. Examples of the substituent include a hydroxyl group,an alkoxy group, a cyano group, a halogen atom, and an ionic hydrophilicgroup.

[0176] Suitable examples of the alkyl group include methyl, ethyl,butyl, isopropyl, t-butyl, hydroxyethyl, methoxyethyl, cyanoethyl,trifluoromethyl, 3-sulfopropyl, and 4-sulfobutyl.

[0177] The cycloalkyl group represented by R¹, R², R³, R⁵, R⁷, R⁸, andR⁹ includes a substituted cycloalkyl group and an unsubstitutedcycloalkyl group.

[0178] As the cycloalkyl group is preferable a cycloalkyl group havingfrom 5 to 12 carbon atoms. Examples of the substituent include an ionichydrophilic group.

[0179] Suitable examples of the cycloalkyl group include cyclohexyl.

[0180] The aralkyl group represented by R¹, R², R³, R⁵, R⁷, R⁸. and R⁹includes a substituted aralkyl group and an unsubstituted aralkyl group.

[0181] As the aralkyl group is preferable an aralkyl group having from 7to 20 carbon atoms. Examples of the substituent include an ionichydrophilic group.

[0182] Suitable examples of the aralkyl group include benzyl and2-phenethyl.

[0183] The aryl group represented by R¹, R², R³, R⁵, R⁷, R⁸, and R⁹includes a substituted aryl group and an unsubstituted aryl group.

[0184] As the aryl group is preferable an aryl group having from 6 to 20carbon atoms. Examples of the substituent include an alkyl group, analkoxy group, a halogen atom, an alkylamino group, and an ionichydrophilic group.

[0185] Suitable examples of the aryl group include phenyl, p-tolyl,p-methoxyphenyl, o-chlorophenyl, and m-(3-sulfopropylamino)phenyl.

[0186] The alkylthio group represented by R¹, R², R³, R⁵, R⁷, R⁸, and R⁹includes a substituted alkylthio group and an unsubstituted alkylthiogroup.

[0187] As the alkylthio group is preferable an alkylthio group havingfrom 1 to 20 carbon atoms. Examples of the substituent include an ionichydrophilic group.

[0188] Suitable examples of the alkylthio group include methylthio andethylthio.

[0189] The arylthio group represented by R¹, R², R³, R⁵, R⁷, R⁸, and R⁹includes a substituted arylthio group and an unsubstituted arylthiogroup.

[0190] As the arylthio group is preferable an arylthio group having from6 to 20 carbon atoms. Examples of the substituent include an alkyl groupand an ionic hydrophilic group.

[0191] Suitable examples of the arylthio group include phenylthio andp-tolylthio.

[0192] As the heterocyclic group represented by R² is preferable a5-membered or 6-membered heterocyclic ring. The heterocyclic ring mayfurther be condensed. As the hetero atom constituting the heterocyclicring are preferable a nitrogen atom, a sulfur atom, and an oxygen atom.Further, the heterocyclic ring may be an aromatic heterocyclic ring or anon-aromatic heterocyclic ring. The heterocyclic ring may further besubstituted. Examples of the substituent are suitably the samesubstituents enumerated later for the aryl group. As the heterocyclicring are enumerated 6-membered nitrogen-containing aromatic heterocyclicrings, with triazine, pyrimidine, and phthalazine being particularlypreferred.

[0193] As the halogen atom represented by R⁸ are suitably enumerated afluorine atom, a chlorine atom, and a bromine atom.

[0194] The alkoxy group represented by R¹, R³, R⁵, and R⁸ includes asubstituted alkoxy group and an unsubstituted alkoxy group.

[0195] As the alkoxy group is preferable an alkoxy group having from 1to 20 carbon atoms. Examples of the substituent include a hydroxyl groupand an ionic hydrophilic group.

[0196] Suitable examples of the alkoxy group include methoxy, ethoxy,isopropoxy, methoxyethoxy, hydroxyethoxy, and 3-carboxypropoxy.

[0197] The aryloxy group represented by R⁸ includes a. substitutedaryloxy group and an unsubstituted aryloxy group.

[0198] As the aryloxy group is preferable an aryloxy group having from 6to 20 carbon atoms. Examples of the substituent include an alkoxy groupand an ionic hydrophilic group.

[0199] Suitable examples of the aryloxy group include phenoxy,p-methoxyphenoxy, and o-methoxyphenoxy.

[0200] The acylamino group represented by R⁸ includes a substitutedacylamino group and an unsubstituted acylamino group.

[0201] As the acylamino group is preferable an acylamino group havingfrom 2 to 20 carbon atoms. Examples of the substituent include an ionichydrophilic group.

[0202] Suitable examples of the acylamino group include acetamide,propionamide, benzamide, and 3,5-disulfobenzamide.

[0203] The sulfonylamino group represented by R⁸ includes a substitutedsulfonylamino group and an unsubstituted sulfonylamino group.

[0204] As the sulfonylamino group is preferable a sulfonylamino grouphaving from 1 to 20 carbon atoms.

[0205] Suitable examples of the sulfonylamino group includemethylsulfonylamino and ethylsulfonylamino.

[0206] The alkoxycarbonylamio group represented by R⁸ includes asubstituted alkoxycarbonylamino group and an unsubstitutedalkoxycarbonylamino group.

[0207] As the alkoxycarbonylamino group is preferable analkoxycarbonylamino group having from 2 to 20 carbon atoms. Examples ofthe substituent include an ionic hydrophilic group.

[0208] Suitable examples of the alkoxycarbonylamino group includeethoxycarbonylamino.

[0209] The ureido group represented by R⁸ includes a substituted ureidogroup and an unsubstituted ureido group.

[0210] As the ureido group is preferable a ureido group having from 1 to20 carbon atoms.

[0211] Examples of the substituent include an alkyl group and an arylgroup.

[0212] Suitable examples of the ureido group include 3-methylureido,3,3-dimethylureido, and 3-phenylureido.

[0213] The alkoxycarbonyl group represented by R⁷, R⁸, and R⁹ includes asubstituted alkoxycarbonyl group and an unsubstituted alkoxycarbonylgroup.

[0214] As the alkoxycarbonyl group is preferable an alkoxycarbonyl grouphaving from 2 to 20 carbon atoms. Examples of the substituent include anionic hydrophilic group.

[0215] Suitable examples of the alkoxycarbonyl include methoxycarbonyland ethoxycarbonyl.

[0216] The carbamoyl group represented by R², R⁷, R⁸, and R⁹ includes asubstituted carbamoyl group and an unsubstituted carbamoyl group.Examples of the substituent include an alkyl group.

[0217] Suitable examples of the carbamoyl group include amethylcarbamoyl group and a dimethylcarbamoyl group.

[0218] The sulfamoyl group represented by R⁸ includes a substitutedsulfamoyl group and an unsubstituted sulfamoyl group. Examples of thesubstituent include an alkyl group.

[0219] Suitable examples of the sulfamoyl group include adimethylsulfamoyl group and a di-(2-hydroxyethyl)sulfamoyl group.

[0220] Suitable examples of the sulfonyl group represented by R⁸ includemethanesulfonyl and phenylsulfonyl.

[0221] The acyl group represented by R² and R⁸ includes a substitutedacyl group and an unsubstituted acyl group. As the acyl group ispreferable an acyl group having from 1 to 20 carbon atoms. Examples ofthe substituent include an ionic hydrophilic group.

[0222] Suitable examples of the acyl group include acetyl and benzoyl.

[0223] The amino group represented by R⁸ includes a substituted aminogroup and an unsubstituted amino group. Examples of the substituentinclude an alkyl group, an aryl group, and a heterocyclic group.

[0224] Suitable examples of the amino group include methylamino,diethylamino, anilino, and 2-chloroanilino.

[0225] The heterocyclic group represented by R⁴, R⁶, and R¹⁰ is the sameas the optionally substituted heterocyclic group represented by B in thegeneral formula (Y-I), and its preferred examples, more preferredexamples and most preferred examples are also the same.

[0226] Examples of the substituent include an ionic hydrophilic group,an alkyl group having from 1 to 12 carbon atoms, an aryl group, analkyl- or arylthio group, a halogen atom, a cyano group, a sulfamoylgroup, an sulfonamino group, a carbamoyl group, and an acylamino group.Each of the alkyl group and the aryl group may further have asubstituent.

[0227] In the general formula (Y-III), Za represents —N═, —NH—, orC(R¹¹)═; Za and Zc each independently represents —N═ or C(R¹¹)═; R¹¹represents a hydrogen atom or a non-metallic substituent. As thenon-metallic substituent represented by R¹¹ are preferable a cyanogroup, a cycloalkyl group, an aralkyl group, an aryl group, an alkythiogroup, an arylthio group, and an ionic hydrophilic group. Each of thesubstituents is synonymous with each of the substituents represented byR¹, and preferred examples thereof are also the same. Examples of askeleton (i.e., a basic structure) comprising two 5-membered rings,which is included in the general formula (Y-III), are given below.

[0228] In the case where each of the foregoing substituents may furtherhave a substituent, examples of the substituent include the substituentsthat may be substituted on the heterocyclic rings A and B of the generalformula (Y-I).

[0229] Specific examples of the dye represented by the general formula(Y-I) (Y-101 to Y-160) will be given below, but it should not beconstrued that the present invention is limited thereto. These compoundscan be synthesized by referring to JP-A-2-24191 and JP-A-2001-279145.

Dye R Y-101 CON(C₂H₅)₂ Y-102 CON(C₄H₉)₂ Y-103 CON(C₆H₁₃)₂ Y-104 COOC₄H₉Y-105 COOC₆H₁₃ Y-106 COC₄H₉ Y-107 CONHC₄H₉ Y-108 CONHC₆H₁₃

Dye R Y-109 COOC₄H₉ Y-110 CONHC₄H₉ Y-111 CON(C₄H₉)₂ Y-112 SO₂NHC₆H₁₃Y-113 SO₂N(C₄H₉)₂ Y-114 NHCOC₆H₁₃ Y-115 NHSO₂C₈H₁₇ Y-116 C₄H₉ Y-117OC₆H₁₃ Y-119

Y-120

Dye R R′ Y-121 CH₃ H Y-122 Ph H Y-123 OC₂H₅ H Y-124 C₄H₉(t) SCH₃ Y-125C₄H₉(t) Ph Y-126 C₄H₉(t) CH₃ Y-127 C₄H₉(t) SC₈H₁₇

Dye R Y-128 CH₂Ph Y-129 C₄H₉ Y-130 C₈H₁₇ Y-131 CONH₂

Dye R Y-132 H Y-133 CH₃ Y-134 Ph Y-135 SCH₃ Y-136

Y-137

Y-138

Y-139

Y-140

Y-141

Y-142

Y-143

Y-144

Y-145

Y-146

Y-147

Y-148

Y-149

Y-150

Y-151

Y-152

Y-153

Y-154

Y-155

Dye R R¹ Y-156 —C₁₆H₃₃ C₄H₉ Y-157 —C₁₆H₃₃ C₂H₅ Y-158 —C₁₄H₂₉ H Y-159—C₁₈H₃₇ H Y-160

CH₃

[0230] While it is essential that the oil-soluble dye is dissolved inthe monomer, it is also important that no crystal deposits with a lapseof time. In general, it is said to be better that a solubility parameter(hereinafter referred to as “SP value”) of a monomer is closed to the SPvalue of an oil-soluble dye. However, since a portion relying on thestructures of a molecule to be dissolved (the oil-soluble dye in thepresent invention) and a solvent (the monomer in the present invention)is present, there may be the case where interpretation cannot be madeonly in terms of the SP value. In the case of the oil-soluble dyesrepresented by the general formulae (Y-I), (Y-II), (Y-III), and (Y-IV),it has been found that the solubility and storage stability with timeare made superior by using the two physical properties of the molarvolume V value and the SP value.

[0231] The SP value is preferably from 26 to 21, more preferably from 25to 21, further preferably from 24 to 21, and most preferably 24 to 22.The V value is preferably from 810 to 270, more preferably from 800 to300, further preferably from 750 to 350, and most preferably from 700 to380.

[0232] Here, the V value (cm³/mole) and SP value (J^(0.5)/cm^(1.5)) arevalues calculated by the Fedors method. The calculation method isdescribed in Polym. Eng. Sci., Vol. 14, pp. 147 (1974).

[0233] Each of the foregoing dyes may be one in which a part of thechromophore is dissociated, thereby first undergoing color developmentinto each color of yellow, magenta, or cyan. In that case, the countercation may be an inorganic cation such as an alkali metal and ammonium,or an organic cation such as pyridinium and a quaternary ammonium salt,or may be a polymer cation having the foregoing cation in a partialstructure thereof.

[0234] In order that the polymerization inhibiting or polymerizationretarding action hardly occurs in the presence of air, the oil-solubledye of the present invention is desired to have a high oxidationpotential to reduce the reactivity with the polymerization initiator oroxygen radicals (such as oxy radical) as generated by the action ofoxygen to monomer radicals (including growth radicals of oligomers andpolymers). By increasing the oxidation potential, not only the curingproperties of the ink are enhanced, but also ozone resistance issimultaneously enhanced because the reactivity with ozone as anelectrophilic agent is lowered.

[0235] Desirably, the oil-soluble dye to be used in the presentinvention has an oxidation potential higher than 1.0 V (vs SCE) It ispreferred that the oxidation potential is higher. The oxidationpotential of the oil-soluble dye is preferably higher than 1.1 V (vsSCE), more preferably higher than 1.2 V (vs SCE), and most preferablyhigher than 1.3 V (vs SCE).

[0236] The measurement method of the value (Eox) of oxidation potentialis described in, for example, Delahay, New Instrumental Methods inElectrochemistry, (1954), by Interscience Publishers; A. J. Bard, etal., Electrochemical Methods, (1980), by John Wiley & Sons; and AkiraFujishima, et al., Denkikagaku Sokuteiho (Electrochemical MeasurementMethods), (1984), by Gihodo Shuppan.

[0237] Concretely, the oxidation potential is measured by dissolving atest sample (1×10⁻⁴ to 1×10⁻⁶ mole/L) in a solvent (such asdimethylformamide and acetonitrile) containing a supporting electrolyte(such as sodium perchlorate and tetrapropylammonium perchlorate) andmeasuring a value:against SCE (saturated calomel electrode) by usingcyclic voltammetry or direct-current polarography. This value maydeviate by about several tens millivolts by influences such as a liquidpotential and a liquid resistance of the sample solution, but it ispossible to guarantee the reproductivity of the potential by charging astandard sample (such as hydroquinone).

[0238] In the present invention, in order to univocally define thepotential, a value (vs SCE) as measured in dimethylformamide containing0.1 moldm⁻³ of tetrapropylammonium perchlorate as a supportingelectrolyte (dye contencentration: 0.001 moldm⁻³) by direct currentpolarography is defined as the oxidation potential.

[0239] The Eox value stands for easiness of the movement of an electronfrom the sample to the electrode. The higher the value (the higher theoxidation potential), the more difficult the movement of the electronfrom the sample to the electrode, i.e., the sample is hardly oxidized.In accordance with the relationship with the structure of a compound,when an electron attractive group is introduced, the oxidation potentialincreases, whereas when an electron donating group is introduced, theoxidation potential decreases. Accordingly, when the Hammett'ssubstituent constant, σp value as a measure of the electron attractivegroup or electron donating group is used, it can be said that byintroducing. a substituent having a large σp value, such as a sulfinnylgroup, a sulfonyl group, and a sulfamoyl group, the oxidation potentialcan be made higher.

[0240] A content of the oil-soluble dye in the ink is preferably from0.05 to 15% by weight, more preferably from 0.1 to 10% by weight, andmost preferably from 0.2 to 6% by weight.

[0241] <Storage stabilizer>

[0242] The storage stabilizer controls undesirable polymerization duringthe preservation of the ink, and ones that can be dissolved in the inkare useful. As the storage stabilizer are enumerated quaternary ammoniumsalts, hydroxylamine salts, cyclic amides, nitrites, substituted ureas,heterocyclic compounds, organic acids, hydroquinone, hydroquinonemonoethers, organic phosphines, and copper compounds, with hydroquinoneand hydroquinone monoethers being preferred. Specific examples includebenzyltrimethylammonium chloride, diethyl hydroxylamine, benzothiazole,4-amino-2,2,6,6-tetramethylpyridine, citric acid, hydroquinonemonomethyl ether, hydroquinone monobutyl ether, and copper napthenate.

[0243] Preferably, an amount of the storage stability to be used isproperly regulated on a basis of the activity of the polymerizationinitiator as used, the polymerization properties of the monomer, and thekind of the storage stability. But, the amount of the storage stabilityto be used is preferably from 0.005 to 1% by weight, more preferablyfrom 0.01 to 0.5% by weight, and most preferably from 0.01 to 0.2% byweight in the ink composition. When the addition amount of the storagestabilizer is too low, the storage stability is inferior, whereas whenit is too high, there is a problem such that curing after the printinghardly occurs.

[0244] <Conductive salt>

[0245] The conductive salt is a solid compound for enhancing theconductivity by dissolution in the ink. In the present invention, sincethere may be a high possibility that the conductive salt deposits duringthe preservation, it is preferred that the conductive salt is notsubstantially used. However, in the case where the solubility of theconductive salt is increased, or one having a high solubility in theliquid component of the ink is used so that the solubility is good, aproper amount of the conductive salt may be added. Examples of theconductive salt include potassium thiocyanate, lithium nitrate, ammoniumthiocyanate, and dimethylamine hydrochloride.

[0246] <Other components>

[0247] The ink composition according to the present invention maycontain other components to be properly chosen depending on the purposeso far as the effects are not hindered. As other components areenumerated known additives such as solvents, polymers, surface tensionadjustors, ultraviolet absorbers, antioxidants, anti-fading agents, andpH adjustors.

[0248] The solvent can be used for the purposes of regulating thepolarity, viscosity and surface tension of the ink, enhancing thesolubility of the oil-soluble dye, regulating the conductivity of theoil-soluble dye, and the regulating the printing performance.

[0249] As the solvent are enumerated water, low-boiling organicsolvents, and high-boiling organic solvents.

[0250] A content of water is preferably 5% or less, more preferably 3%or less, and further preferably 0.5% or less. Most preferably, water isnot substantially contained. Here, what water is not substantiallycontained means the case where water is contained as a component otherthan the major components in the material as used, namely, water iscontained as an impurity, and water is not intentionally added. The casewhere the content of water is too high is not desired from the followingreasons. That is, in the case where a non-water absorbing material to berecorded is used, the material is hardly dried, and the ink becomesnon-uniform with time, or the ink is liable to cause precipitation orturbidity by deposition of the dye.

[0251] The low-boiling organic solvent is an organic solvent having aboiling point of 100° C. or lower. Taking into consideration theenvironmental pollution, it is desired that the low-boiling organicsolvent be not used. In the case where it is used, it is preferred touse one having high safety. The solvent having high safety as referredto therein is a solvent having a managed concentration (an indexexpressed by the working environmental evaluation standards), and themanaged concentration is preferably 100 ppm or higher, and morepreferably 200 ppm or higher. As the low-boiling organic solvent areenumerated alcohols, ketones, esters, ethers, and hydrocarbons. Specificexamples include methanol, 2 -butanol, acetone, methyl ethyl ketone,ethyl acetate, and tetrahydrofuran.

[0252] The high-boiling organic solvent is an organic solvent having aboiling point higher than 100° C. The high-boiling organic solventpreferably has a boiling point of 150° C. or higher, and more preferably170° C. or higher. As the high-boiling organic solvent are enumeratedpolyhydric alcohols, aliphatic carboxylic acid esters, phosphoricesters, and hydrocarbons. Specific examples include diethylene glycol,trimethylolpropane, dibutyl phthalate, 2-ethylhexyl benzoate, andalkylnaphthalenes. These solvents may be a liquid or a solid at normaltemperature depending on the purpose.

[0253] The solvent may be used singly or in admixture of two or morethereof. An amount of the solvent to be use is preferably 20% by weightor less, more preferably 10% by weight or less, and most preferably 5%by weight or less. When the addition amount of the high-boiling organicsolvent is too high, the drying properties are worsened, the resistanceto rubbing of the image after curing is worsened, and the image aftercuring is liable to peel apart; and when the addition amount of thelow-boiling organic solvent is too high, the printing properties areworsen due to evaporation of the solvent after long-term preservation,the generation of the organic solvent vapor adversely affects thehealth, and an ignition problem occurs. Therefore, these are notpreferred.

[0254] The polymer can be used for regulating the polarity and viscosityof the ink, enhancing the solubility of the oil-soluble dye, andregulating the light fastness and adhesion of the ink after curing to amaterial to be recorded. While the polymer may be dissolved in the inkor may be a fine dispersion, it is preferred to dissolve the polymer inthe ink from the standpoints of the storage stability and ejectionproperties of the ink.

[0255] In the case where the polymer is dissolved in the ink, oneshaving high affinity with the dye and the monomer are preferred. Fromthe standpoint that an increase in viscosity of the ink hardly occurs,the polymer preferably has a molecular weight of 50,000 or less, morepreferably of 20,000 or less, and most preferably 10,000 or less. As thepolymer are enumerated vinyl polymers, polyurethanes, and polyesters.Specific examples include polybutyl acrylate, poly(isobutylmethacrylate-hydroxyethyl acrylate) (copolymerization weightratio=95:5), poly(isopropyl acrylate-tetrahydrofurfuryl acrylate(copolymerization weight ratio. 70:30), poly(butylmethacrylate-N-methoxymethyl acrylamide) (copolymerization weightratio=80:20), and polybutyl acrylate-polydimethylsiloxane blockcopolymer (copolymerization weight ratio=90:10).

[0256] In the case where the polymer is fine dispersion, it is essentialthat the polymer is not substantially dissolved in the monomer. Further,it is preferred that the polymer hardly swells or does not swell. Thedispersion in the ink preferably has a particle size of 1 μm or less,more preferably 0.5 μm or less, and most preferably 0.1 μm or less. Asthe polymer are enumerated vinyl polymer fine particles, polyurethanefine particles, polyester fine particles, and urethane-vinyl compositeparticles. Specific examples include poly(acrylonitrile-ethylacrylate-ethylene glycol dimethacrylate) (copolymerization weightratio=60:37:3) and poly(styrene-butadiene) (copolymerization weightratio=50:50).

[0257] The polymer may be used singly or in admixture of two or morethereof. An amount of the polymer to be used is preferably from 0 to 40%by weight, more preferably from 0 to 30% by weight, and most preferablyfrom 0 to 20% by weight.

[0258] With respect to the surface tension adjustor, the ultravioletabsorber, the antioxidant, the anti-fading agent, and the pH adjustor,those as disclosed in JP-A-2001-181549 may be used.

[0259] While the physical properties of the ink reply on the printingdevice, the ink composition preferably has a viscosity of from 5 to 100mPa·s, and more preferably from 10 to 80 mPa·s. Further, the inkcomposition preferably has a surface tension of from 20 to 60 mN/m, andmore preferably from 30 to 50 mN/m.

[0260] (Image recording method)

[0261] In the image recording method according to the present invention,the image formation can be carried out using the ink composition by aknown recording method. In particular, in the case where the imagerecording method is applied to the inkjet recording method, an inknozzle to be used is not particularly limited but can be properly chosenaccording to the object.

[0262] In the ink composition according to the present invention can besuitably printed on a known material to be recorded. As the material tobe recorded are enumerated plain papers, resin-coated papers, specialinkjet papers, films, electrophotbgraphic shared papers, cloths, glass,metals, and ceramics. The materials to be recorded are described in, forexample, JP-A-2001-181549.

[0263] The ink composition according to the present invention may beapplied to any inkjet recording mode. As the inkjet recording mode aresuitably employed a charge control mode for ejecting the ink utilizingan electrostatic induction force; a drop-on-demand mode (pressure pulsemode) utilizing an oscillation pressure of piezoelectric elements; anacoustic inkjet mode for converting electric signals into acousticbeams, irradiating the ink with the acoustic beams and ejecting the inkutilizing a radiation pressure; and a thermal inkjet (bubble jet) modefor heating the ink to form foams and utilizing a generated pressure.Among them are preferable a charge control mode, a pressure pulse mode,and an acoustic inkjet mode, with a charge control mode and a pressurepulse mode being particularly preferred.

[0264] The inkjet recording mode includes a mode for injecting manysmall-volume inks having a low concentration, called a photo-ink; a modefor using a plurality of inks having substantially the same hue and adifferent concentration to improve the image quality; and a mode forusing a colorless transparent ink.

[0265] The curing method of the image varies depending on the kind ofthe radiations to be used. In the case of using ultraviolet rays orvisible rays, a low-pressure mercury vapor lamp, a high-pressure mercuryvapor lamp, a metal halide lamp, a carbon arc lamp, a xenon lamp, and achemical lamp can be used. Of these are preferable a low-pressuremercury vapor lamp, a high-pressure mercury vapor lamp, and a metalhalide lamp, with a high-pressure mercury vapor lamp-and a metal halidelamp being more preferred. In the case of using ultraviolet rays orvisible rays, an irradiation energy is preferably from 1 to 1,000mJ/cm², more preferably from 10 to 750 mJ/cm², further preferably from10 to 500 MJ/cm², and most preferably from 10 to 250 mJ/cm². In the casewhere the irradiation energy is small, since the ink is hardly cured, orit is necessary to increase the sensitivity of the ink, the storagestability of the ink tends to become inferior. On the other hand, in thecase where the irradiation energy is large, ozone or heat is generated,or a part of the dye may be possibly decomposed, and hence, such is notdesired.

EXAMPLE

[0266] The present invention will be described below with reference tothe Examples, but it should not be construed that the present inventionis limited thereto. Incidentally, all “parts” and “%” are “parts byweight” and “weight %”, respectively unless otherwise indicated.

Example 1

[0267] <Preparation of Ink 01>

[0268] To a mixture of 49 pats of pentaerythritol tetraacrylate, 25parts of hexamethylene-1,6-diacrylate, and 15 parts of N-vinylformamidewere added 2.5 parts of an oil-soluble dye (AII-17), 1.2 parts of afluorine-based nonionic surfactant, 4 parts ofbis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 1 partof 1-hydroxy-:cyclohexyl phenyl ketone, 2.3 parts of triethanolamine,and 0.02 parts of hydroquinone monobutyl ether, and the mixture wasdissolved. The solution was subjected to filtration by a 0.45-μm filterto prepare an inkjet recording ink.

[0269] <Preparation of Ink 02>

[0270] To a mixture of 39 parts of pentaerythritol tetraacrylate, 24pats of dipentaerythritol tetraacrylate, 9 parts of ethylene glycoldiacrylate, 5 parts of diethylaminoethyl acrylate, 7 parts ofN-vinylformamide, 5 parts of pentaerythritol, and 15 parts of methylethyl ketone were added 2.5 parts of an oil-soluble dye (AII-17), 1.2parts of a fluorine-based nonionic surfactant, 2 parts ofbis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 5 partsof 1-hydroxy-cyclohexyl phenyl ketone, and 0.02 parts of hydroquinonemonobutyl ether, and the mixture was dissolved. The methyl ethyl ketonewas distilled off under reduced pressure at 5° C., and the residue wassubjected to filtration by a 0.45-μm filter to prepare an inkjetrecording ink.

[0271] <Preparation of Ink 03>

[0272] To a mixture of 40 parts of ditrimethylolpropane tetraacrylate,34 parts of pentaerythritol tetraacrylate, and 9 parts oftetrahydrofurfuryl acrylate were added 2.5 parts of an oil-soluble dye(AII-17), 5 parts of polybutyl methacrylate (number average molecularweight: 12,000), 1.2 parts of a fluorine-based nonionic surfactant, 3parts of bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide,2 parts of 1-hydroxy-cyclohexyl phenyl ketone, 2 parts ofdiethanolamine, 1.3 parts of potassium thiocyanate, and 0.02 parts ofhydroquinone monobutyl ether, and the mixture was dissolved. Thesolution was subjected to filtration by a 0.45 μpm filter to prepare aninkjet recording ink.

[0273] <Preparation of Inks 04 to 09>

[0274] Each of inkjet recording inks of Inks 04 to 09 was prepared inthe same manner as in the preparation of the Ink 02, except for changingthe oil-soluble dye (AII-17) in the preparation of the Ink 02.

[0275] <Preparation of Inks 10 to 15>

[0276] Each of inkjet recording inks of Inks 10 to 15 was prepared inthe same manner as in the preparation of the Ink 03, except for changingthe addition amount of the hydroquinone monobutyl ether in thepreparation of the Ink 03.

[0277] Using each of the thus prepared inkjet recording inks, an imagewas recorded on a PET film, which was then subjected to exposure withlight at 200 mJ/cm² by a metal halide lamp.

[0278] The inks and the obtained recorded samples were evaluated in thefollowing methods. The results obtained are shown in Table 1.

[0279] <Storage stability>

[0280] The ink was preserved at 60° C. for 30 days, and then evaluatedfor the state and the filtration properties by a 0.45-μm filter.

[0281] The storage stability was evaluated in accordance with thefollowing three grades.

[0282] A: The ink does not change, and the filtration properties by a0.45-μm filter are good (good).

[0283] B: The ink does not change, but the filtration properties by a0.45-μm filter are bad (allowable).

[0284] C: The ink gelates or is increased in viscosity (bad).

[0285] <Curing properties>

[0286] The recorded image was observed and evaluated in accordance withthe following three grades.

[0287] A: The ink is not sticky (good).

[0288] B: The ink is slightly sticky but does not stain a material to becontacted (allowable).

[0289] C: The ink is extremely sticky (bad).

[0290] <Color tone>

[0291] The color tone was evaluated in accordance with the followingthree grades.

[0292] A: The best

[0293] B: Good

[0294] C: Bad

[0295] <Water resistance>

[0296] The image-formed PET film was immersed in water for one minuteand spontaneously dried at room temperature to observe blotting,peeling, and change in color tone.

[0297] The water resistance was evaluated in accordance with thefollowing two grades.

[0298] A: Neither blotting nor peeling is observed, and the color tonedoes not change.

[0299] B: Any one of blotting, peeling, and change in color is observed.

[0300] <Light fastness>

[0301] The image-formed PET film was irradiated with a xenon light(85,000 lx) using a weatherometer (Atlas C. 165) for 3 days, and theimage density before and after the irradiation with a xenon light wasmeasured using a reflection densitometer (X-Rite 310TR) and evaluated asa dye retention rate.

[0302] The light fastness was evaluated in accordance with the followingthree grades.

[0303] A: The dye retention rate is 80% or more.

[0304] B: The dye retention rate is less than 80% and 70% or more.

[0305] C: The dye retention rate is less than 70%. TABLE 1 Curing No.Oil-soluble dye Storage stability properties Color tone Water resistantLight fastness Remarks Ink 01 AII-17 A A A A A Invention Ink 02 AII-17 AA A A A Invention Ink 03 AII-17 A A A A A Invention Ink 04 AII-19 A A AA A Invention Ink 05 AII-21 A A A A A Invention Ink 06 AII-3 A A A A AInvention Ink 07 AII-7 A A A A A Invention Ink 08 DD-1 A C A A BComparison Ink 09 DD-2 A C A A B Comparison Storage stabilizer CuringNo. (weight %) Storage stability properties Color tone Water resistantLight fastness Remarks Ink 10 0 C A A A A Invention Ink 11 0.005 B A A AA Invention Ink 12 0.01 A A A A A Invention Ink 13 0.04 A A A A AInvention Ink 14 0.9 A B A A A Invention Ink 15 1.1 A C A A A Invention

[0306] As is clear from Table 1, the Ink 10 not containing the storagestabilizer does not have storage stability; and the Ink 15 having alarge quantity of the storage stabilizer is superior in the storagestability but is bad in the curing properties. The inkjet recording inksof the present invention were superior in the storage stability andcuring properties, and when recorded on the PET having no liquidabsorbing properties, exhibited superior properties in the color tone,water resistance and light fastness.

Example 2

[0307] Recording samples were prepared in the same manner as in Example1, except that the image recording was carried out while changing thematerial to be recorded. The samples-were evaluated in the same manneras in Example 1, except for the oxidation potential and ozoneresistance.

[0308] <Ozone resistance>

[0309] The ozone resistance was evaluated by measuring the image densitybefore and after preserving the sample under a condition having an ozoneconcentration of 1.0 ppm for 5 days using a reflection densitometer(X-Rite 310) and determining the dye retention rate.

[0310] The evaluation was made in accordance with the following threegrades: the case where the dye retention rate was 90% or more isdesignated as “A”, the case where the dye retention rate was 70% or morebut less than 90% is designated as “B”, and the case where the dyeretention rate was less than 70% is designated as “C”, respectively.

[0311] <Oxidation potential>

[0312] A definite amount (converted as molecular weight) of the dye wasweighed and measured in N,N-dimethylformamide containing 0.1 moldm⁻³ oftetrapropylammonium perchlorate (dye concentration: 0.001 moldm⁻³) as asupporting electrolyte by direct current polarography, to determine avalue of oxidation potential. In a polarography unit, a carbon (GC)electrode was used as a work electrode and a rotating platinum electrodewas used as a counter electrode; an oxidation wave obtained by sweepingat the oxidation side was subjected to linear approximation; and amiddle point between an intersection with its peak value and anintersection with the residual current value was defined as the value ofoxidation potential (vs SCE). The measurement results of thephthalocyanine compounds used in the Examples and the comparativecompounds were shown in Table 2. TABLE 2 Material to be Oxidation CuringWater Light Ozone No. Ink No. recorded potential properties Color toneresistance fastness resistance Remarks 1 Ink 02 Plain paper 1.15 A A A AA Invention 2 Ink 05 Plain paper 1.27 A A A A A Invention 3 Ink 09 Plainpaper 0.75 C A A B A Comparison 4 Ink 01 Photo-glossy 1.15 A A A A AInvention paper 5 Ink 05 Photo-glossy 1.27 A A A A A Invention paper 6Ink 09 Photo-glossy 0.75 C A A B C Comparison paper 7 Ink 01 Aluminum1.15 A A A A A Invention sheet 8 Ink 05 Aluminum 1.27 A A A A AInvention sheet 9 Ink 09 Aluminum 0.75 C A A B B Comparison sheet

[0313] As is apparent from the results shown in Table 2, the inks of thepresent invention could form good images on both of the conventionalpaper and the non-liquid absorbing material to be recorded and weresuperior in the curing properties, color tone, water resistance, lightfastness, and ozone resistance. The oxidation potential of the dyeshaving good curing properties, light fastness and ozone resistance ishigher than about 1.0.

Example 3

[0314] <Preparation of Ink 30>

[0315] To a mixture of 39 parts of pentaerythritol tetraacrylate, 35parts of dipentaerythritol hexaacrylate, 9 parts of ethylene glycoldiacrylate, 6 parts of diethylaminoethyl acrylate, and 15 parts ofmethyl ethyl ketone were added 3.0 parts of an oil-soluble dye (Y-156),1.2 parts of fluorine-based nonionic surfactant, 2 parts ofbis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 5 partsof 1-hydroxy-cyclohexyl phenyl ketone, and 0.02 parts of hydroquinonemonobutyl ether, and the mixture was dissolved. The methyl ethyl ketonewas distilled off in vacuo at 5° C., and the residue was subjected tofiltration by a 0.45-μm filter to prepare an inkjet recording ink.

[0316] <Preparation of Inks 31 to 36>

[0317] Each of inkjet recording inks of Inks 31 to 36 was prepared inthe same manner as in the preparation of the Ink 30, except for changingthe oil-soluble dye (Y-156) in the preparation of the Ink 30.

[0318] Recording samples were prepared in the same manner as inExample 1. The recording samples were evaluated for the curingproperties, color tone, water resistance, and light fastness except forthe stability in the same manner as in Example 1. Any of the recordingsamples exhibited rank “A” in the curing properties, color tone, waterresistance, and light fastness except for the stability.

[0319] <Stability>

[0320] The ink was preserved at 25° C. for 7 days, and then evaluatedfor the state and the filtration properties by a 0.45-μm filter.

[0321] The storage stability was evaluated in accordance with thefollowing three grades.

[0322] A: The ink does not change, and the filtration properties aregood (good).

[0323] B: The ink is slightly turbid or slightly generates a precipitate(allowable).

[0324] C: The ink largely generates coagulation or gelates, or isincreased in viscosity (bad). TABLE 3 Oil-soluble Ink dye V value SPvalue Stability Remarks Ink 30 Y-156 804 20.9 B Invention: The SP valueis smaller than the recommended value. Ink 31 Y-157 788 21.0 A InventionInk 32 Y-158 688 21.6 A Invention Ink 02 Y-120 486 25.3 A Invention Ink33 Y-101 350 26.5 B Invention: The SP value is larger than therecommended value.

[0325] TABLE 4 Oil-soluble Ink dye SP value V value Stability RemarksInk 34 Y-116 25.0 267 B Invention: The SP value is smaller than therecommended value. Ink 35 Y-117 24.4 303 A Invention Ink 31 Y-157 21.0788 A Invention Ink 36 Y-159 21.0 817 B Invention: The SP value islarger than the recommended value.

[0326] As is apparent from the results shown in Tables 3 and 4, thestability of the inks using the dye of the general formula (Y-I) isrelated to the solubility parameter SP value (J^(0.5)/cm^(1.5)) and themolar volume V value (cm³/mole). In the case of the oil-soluble dyeshaving a preferred V value range of from 800 to 270 as shown in Table 3,the Ink 30 having an SP value smaller than 21 and the Ink 33 having anSP value larger than 26 tend to be inferior in the stability. In thecase of the oil-soluble dyes having a preferred SP value range of from26 to 21 as shown in Table 4, the Ink 34 having a V value smaller than270 and the Ink 36 having a V value larger than 810 tend to be inferiorin the stability. It can be understood that in the case where thesolubility parameter SP; value is in the range of from 26 to 21, and themolar volume V value is in the range of from 810 to 270, the inkstability is particularly superior.

Example 4

[0327] The following ink sets of four colors were prepared, and afull-color image was recorded and evaluated in the same manner as inExample 1. As a result, the obtained image was superior in any of thecuring properties, color tone, water resistance, and light resistance.All of the dyes as used had an oxidation potential of 1.1 V or more.

[0328] <Yellow ink>

[0329] An inkjet recording yellow ink was prepared in the same manner asin the preparation of the Ink 30 in Example 3, except for using 3.0parts of an oil-soluble dye (Y-120) in place of 3.0 parts f theoil-soluble dye (Y-156) in the preparation of the Ink 30.

[0330] <Magenta ink>

[0331] An inkjet recording magenta ink was prepared in the same manneras in the preparation of the Ink 30 in Example 3, except for using 2.0parts of an oil-soluble dye (M-1) in place of 3.0 parts f theoil-soluble dye (Y-156) in the preparation of the Ink 30.

[0332] <Cyan ink>

[0333] An inkjet recording cyan ink was prepared in the same manner asin the preparation of the Ink 30 in Example 3, except for using 2.0parts of an oil-soluble dye (AII-17) in place of 3.0 parts f theoil-soluble dye (Y-156) in the preparation of the Ink 30.

[0334] <Black ink>

[0335] An inkjet recording black ink was prepared in the same manner asin the preparation of the Ink 30 in Example 3, except for using 1.6parts of an oil-soluble dye (M-1), 2.6 parts of an oil-soluble dye(II-17), and 1.8 parts of an oil-soluble dye (Y-120) in place of 3.0parts f the oil-soluble dye (Y-156) in the preparation of the Ink 30.

[0336] According to the present invention, it is possible to provide anink composition that can form a high-quality image on not only liquidabsorbing materials to be recorded but also non-liquid absorbingmaterials to be recorded, is superior in curing properties in air, andis superior in storage, stability, color tone, light fastness and waterresistance of ink, and also to provide an image recording method.

[0337] The entitle disclosure of each and every foreign patentapplication from which the benefit of foreign priority has been claimedin the present application is incorporated herein by reference, as iffully set forth herein.

[0338] While the invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

What is claimed is:
 1. A radiation-curable ink composition comprising amonomer having a polymerizable group selected from the group consistingof an acryloyl group, a methacryloyl group, an allyl group, and a vinylgroup, an oil-soluble dye, and from 0.005 to 1% by weight of a storagestabilizer, wherein the oil-soluble dye is dissolved in the ink.
 2. Theradiation-curable ink composition as in claim 1, further comprising aphotopolymerization initiator.
 3. The radiation-curable ink compositionas in claim 1, which does not substantially contain water or conductivesalts.
 4. The radiation-curable ink composition as in claim 1, wherein acontent, of a dispersion medium other than the monomer, or a solvent is20% by weight or less.
 5. The radiation-curable ink composition as inclaim 1, wherein the oil-soluble dye has an oxidation potential ishigher than 1.0 V against SCE.
 6. The radiation-curable ink compositionas in claim 1, wherein the oil-soluble dye is at least one memberselected from cyan dyes, magenta dyes, yellow dyes, and black dyes. 7.The radiation-curable ink composition as in claim 1, wherein theoil-soluble dye is at least one member selected from dyes represented bythe following general formula (I):

wherein Q represents an atomic group necessary such that the compoundrepresented by the general formula (I) absorbs light in a visible regionand/or a near infrared region; A represents —NR⁵R⁶ or a hydroxyl group;R⁵ and R⁶ each independently represents a hydrogen atom, an alkyl group,an aryl group, or a heterocyclic group; B¹ represents, ═C(R³)— or ═N—;B² represents —C(R⁴)═ or —N═; R¹, R², R³, and R⁴ each independentlyrepresents a hydrogen atom or a substituent; and R¹ and R², R¹ and R⁵,R⁵ and R⁶, R³ and R⁵, or R³ and R⁴ may be taken together to form a ring;dyes represented by the following general formula (A-I):

wherein X₁, X₂, X₃, and X₄ each independently represents a groupselected from —SO—Z, —SO₂—Z, —SO₂NR₁R₂, —CONR₁R₂, —CO₂R₁, and a sulfogroup; Z represents a substituted or unsubstituted alkyl group, asubstituted or unsubstituted cycloalkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group; R₁ and R₂ each independentlyrepresents a hydrogen atom, a substituted or unsubstituted alkyl group,a substituted or unsubstituted cycloalkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group, provided that R₁ and R₂ do notrepresent a hydrogen atom at the same time; M represents a hydrogenatom, a metal element, a metal oxide, a metal hydroxide, or a metalhalide; Y₁, Y₂, Y₃, and Y₄ each independently represents a hydrogen atomor a monovalent substituent; and a₁ to a₄ and b₁ to b₄ represent thenumbers of X₁ to X₄ and Y₁ to Y₄, respectively and each independentlyrepresents an integer of from 0 to 4, provided that the total sum of a₁to a₄ is 2 or more and 16 or less; and dyes represented by the followinggeneral formula (Y-I): A—N═N—B  (Y-I) wherein A and B each independentlyrepresents an optionally substituted heterocyclic group.
 8. An ink setof the radiation-curable ink composition as in claim 1, comprising threeinks of a magenta ink containing the dye represented by the-generalformula (I); a cyan ink containing the dye represented by the generalformula (A-I), and a yellow ink containing the dye represented by thegeneral formula (Y-I).
 9. An image recording method comprisingundergoing recording using the radiation-curable ink composition as inclaim 1 and then irradiating with radiations to achieve curing.
 10. Theimage recording method as in claim 9, wherein the recording is achievedby any one inkjet mode of charge control mode, pressure pulse mode, andacoustic inkjet mode and then irradiating with radiations to achievecuring.